Interesting, there was zero MSX here. Commodore owned the $300 market, Atari tried really hard and Sinclair seemed like toys. Apple owned the schools but was very expensive, IBM was more for business but the gamers kept pumping out new upgrade cards. I don't know anything about MSX but the manufacturers carried that industrial design over and they had some really beautiful equipment but I've never seen any in person.
I would be surprised if there wasn't the odd American music shop selling the very music orientated CX5M. When I went to Spain in the late 1980s I was surprised to find lots of new MSX for sale in places like department stores. As for Japan check out this insane two part video. I didn't realise that Sharp made MSX but there again every other Japanese manufacturer you can think of had a go. p.s. Do you realise the M in MSX stands for Microsoft as they came up with the standard.