Vivado has free and paid tiers. The free tiers ("WebPack") support their a myriad of their smaller devices (which includes the Kria boards). The larger devices (Virtex, etc.), however, are generally only supported by the paid versions of Vivado.
It's inconvenient for hobbyists, sure, but for enterprise uses the cost of Vivado for a team is largely inconsequential (which I suspect is why they get away with this).
It's inconvenient for hobbyists, sure, but for enterprise uses the cost of Vivado for a team is largely inconsequential (which I suspect is why they get away with this).