Account Sync with consoles

Why is this still not available? I would gladly dump some money into the game if I knew my account would be available on my Xbox, Switch, Mobile and PC. There seems to be an FAQ on this saying “platform and legal reasons” are why it’s not available but this simply isn’t true at all. Diablo 2 has this feature, I’m able to play on my Xbox, switch and PC and the account is synced across all 3 devices so what’s the REAL reason?

Sony/Microsoft etc don’t like crossplay in general because they don’t want people spending money on other platforms other than their own.

They allow it with certain really popular games but want to keep all the income on the platform it is played the most on.

Many games allow a PC to Xbox synch. It would be nice if we get at least that.

So it’s because of the tax they apply to the microtransactions? As far as I know Diablo 2 doesn’t have microtransactions.