I'm sorry I didn't make this clear in the video and I've altered the video title to clarify. Here's a clarification:
People are commenting that MSX sold really well and it didn't fail. Yes, I agree, and I said that in the video. It sold well in Japan, South Korea, the Middle East and other emerging markets. Non-Japanese MSX machines like Phillips sold well in The Netherlands. But the subject of the video is why Japanese branded computers failed to take a hold in Western markets, Europe and North America, and Japanese branded MSX machines failed to do that compared to rival computers. I plan to do a full MSX video in the future covering it from a wider perspective.
My reasoning on why Japanese branded MSX computers failed in North America is that they were hardly sold there, just Yamaha I believe. My reasoning on why Japanese branded MSX computers failed in Europe is the lack of Japanese branded MSX computer adverts in computer magazines after 1985, and the lack of interest of third party sellers to stock them. That's the concrete evidence I can find, computer magazines through archive.org (I read a LOT of computer magazines from 1978 to 1986 to research this video).
I said in the video "it’s generally agreed that at least 3 million MSX computers were sold in Japan", but even that's based on various hearsay reports, which is why I asterisk it. There's reports of up to 10M machines sold worldwide, but these don't have good sources to back them up. Even the low end, 3M in Japan, MSX is a hit, but again, that's not the subject of this video. If you find a reliable source for Japanese branded MSX European computer sales, then please put it below. That is a source from the manufacturer or a journalist, i.e. someone who's been paid money to independently research the number.

I love the arrow keys on the MSX computers. They made games more playable.

They didn't fail, they sold... They just became obsolete like every other 8bit machine. None of them were really trying to take over the industry like IBM because none had the mean to do so. This doesn't mean they failed.

”They focused on technology that always seemed a couple years out of date”

Sharp X68000

I grew up with MSX computer, we got a Philips MSX in the house (VG8020 with cassette) and later upgraded to a MSX2. Lots of friends had a Sony or Phillips MSX2 so it was easy to share and copy games. There was also an MSX at my school, I remember the Logo software with the little turtle. All the Konami game cartridges were very collectable. Just 1 name makes the whole MSX system a succes; the original Metal Gear (I hear the music typing this :) ). We had so much fun with these machines, and found out there were big fairs in Tilburg and Zandvoort. This scene was alive in the '90s! The stuff that some managed to program on relatively simple machines was amazing. For me the MSX was not a fail at all.

They only failed from the point of view of a bubble. Here where I'm from, I could similarly say the Spectrum or Commodore were massive failures

MSX was very popular in the Netherlands with Philips supporting it.  The Japanese cartridge software available for the MSX was pretty impressive especially from Konami.  The lack of smooth scrolling on the MSX was a drawback for games. I can remember Boots in the UK stocking the MSX computers briefly but can't ever remember seeing any shelves of software for it.

The Sharp X68000 was the stuff of dreams and ran rings around the Amiga with many arcade accurate ports.  It was a shame that it was never released in the UK.

It was somewhat big in Brazil.
The cartridge system was so nice. I had a 80 column cartridge for better programming and a memory expansion for higher quality games. 😅

When I visited my brother’s office in Japan in 2010 I saw he had an MSX computer on his desk. I had no idea what it was. My brother said he didn’t really know how to use it except it was the only way to connect to the corporate servers, and he just knew just enough to do that. Suddenly I realized I had been unaware of this entire class of computers for 30 years!

Not a fail worldwide. Huge sucess in Brazil.

In America, only Yamaha widely promoted an MSX system, but sold primarily as a music creation workstation with their own renowned synthesizer chips.

Great video, it was like a walk through my computer history. My first computer was a Video Genie, followed by a Sharp MZ80k. The Sharp might not have been very popular, but I still have my one and it still works! After owning the Sharp for a few years, I changed my main computer to a Sony HitBit MSX. This also still works and I have lots of excellent Konami games for it. So, they might not have proved mega popular at the time, but both my Sharp and Sony are still working 45 years later!

Many schools in developing countries adopted the MSX standard. Cuba, the Soviet Union and (to a limited extent) Poland adopted the MSX standard for use in schools.

Those Epson printer ads are really well done. Clean layout, eye catching photos, clear typeface, simple message.

I was a student back in 1986 and I remember there was a MSX computer in the music department next to a mixer, 8-track tape....
I can't remember the details except that the computer had MIDI interface build in as well as some music software and synth audio chips onboard, so those of us that was tech inclined could use the MSX together with a Yamaha synth keyboard and a Roland drum machine. Only the teacher that ran the music department didn't really understand tech and so the MSX had no storage option ie. no tape deck or disc drive, much to the frustration of those that tried to use the MIDI thing which was really cutting edge. It did not help that the manual for the MSX was nowhere to be found, and as this was before the internet - well what a waste.

There was one MSX machine that got a little traction in the West, the one from Yamaha that had one of their expensive FM synthesizers built in.

In the U.K. there were tonnes of msx machines for sale. Their games were sold in boots for instance next to other 8bit software. Man it was good when software was sold everywhere. Made shopping as a kid way more fun.

MSX was another level from anything else available in USSR schools. Nice screens and sound ! Games were looking so much better on them! Loved MSX back in 80s.

The MSX, PC-88, and PC-98 were all extremely successful home computers. Your terribly eurocentric worldview does not change this fact.

The MSX is such a great little machine.