Because they earn more from entry cards than high end cards, that's why high end cards are only manufactured in limited quantities. Look at Intel, everybody knows their graphic processors are crap but they still dominate the market.  There are more Intel IGPs used than IGP and discrete cards from bot AMD and NVIDIA combined. Gamers, BTC miners, BOINCers are just pieces of rocks in the middle of a desert made-up of ordinary users.

I cant help but laugh at people commenting on the reviews of entry level cards. "Why did AMD/NVIDIA waste their time in this %@#$? Blah, blah, blah.""