ok that makes sense
but im not sure if Japan wants to get rid of its type 90s for type 10s. There is a huge size and weight difference between them, with the Type 10 being closer towards a lighter tank like some of the Soviet T series. My understanding is that the Type 10 is supposed to supplement the Type 90s, not replace them. The type 90s are intended for use in Hokkaido which has more flat space. But realistically, either way, I can't see Japan exporting its tanks anytime soon, even with recent export policy changes.
Current tank producers seem to be limited to Japan, South Korea, China, Germany, India, Turkey, and the US as far as new builds go.
the UK is basically upgrading their Challenger 2s into 3s. Not sure if the Merkava Mk5 are new builds or upgrades.