Honestly, I suspect the Tesla
bicycle that Musk teased in an interview has more of a chance of going mainstream in Japan than any car that Tesla or Musk has discussed publicly, especially as it seems that the $25k Tesla will be a Model 3 variant set up solely as a robotaxi.
...except the Japanese market already has
plenty of
domestic market
e-bikes. (All links in Japanese, but Google Translate worked well enough for me to find those pages, and the gist of what's going on likely doesn't require translation either.)
And Japanese e-bike law is similar to European e-bike law, but with an additional restriction limiting power output to 2x what the rider puts in up to 10 km/h, ramping down from there to zero output at 24 km/h. Basically meaning that a Tesla e-bike can't compete on performance (whereas in Europe, despite the 25 km/h speed limit and "250 W" continuous output limit, intermittent power is effectively unlimited during pedal assist, so performance off the line can still be considered), leaving efficiency/range, cost, and features as things that Tesla would be able to compete on.