I always had this in mind from when OEM liquid cooling went popular. The vega 64 liquid had great temps with a 120mm or 140mm radiator ( dont remember which one it had) and i dont think they are expensive so why are companies like msi and asus not implementing this?
I mean gigabyte had done some steps towards liquid and water cooling solutions on gpus. Personally if i was to get a high end model i wouldnt mind spending 100$ more to get liquid cooling and in return had temperatures in late 40s to 50s on full load instead of 70-75 or even 80s in some cases.
Except from the performance gains i think that keeping to temp that low may in some cases even help with the longevity of the card.
Sure there are solutions like the nzxt kraken g12 that can create a socket for a kraken x62 for example, but not all people feel comfortable meshing around with their gpu and in some counties opening it may even break your warranty.