Maybe you can make each version cost the current amount minus a quarter of the cost of each other version you buy up to two other versions, or minus a dollar for each version you buy after that. Mojang may compromise on that if it encourages people to buy in multiple platforms.
that makes no business sense, and Mojang is a business.
you are suggesting someone could buy say the mobile version, which i got in a google store sale one year for £1 and by linking that i can get the PC version for free which costs £18?
no, i basically mean that you reduce the price i got it for 4$ so i get 4$ off if you link it you will get 1$ off also i i can link my ps account witch i bought minecraft for 18$ i will get minecraft free because I already bought it