Larger and larger mining farms are not what's increasing selling pressure. To the contrary, the larger the farm the cheaper the electricity and the cheaper the hardware to better the operating margin becomes.
A high operating margin gives miners the option to retain more of the mined Bitcoins while a low operating margin forces the miner to sell or at least get more capital by other means to pay bills.
Mining farms are in the business of mining, not risk taking on currency fluctuation. Once gain if they're so profitable in mining the logical thing is to reinvest that income and expand the profitable mining operation, not horde your inventory in hopes it goes up. Just like a gold mining, i'm assuming they sell most of their resources as soon if not before they get it, they don't speculate on price swings (much).
And once again there are 3600BTC mined EVERY day. Either by mega farms or solo miners across the glove. In both cases i think everyone agrees that MAJORITY of those BTC will end up on the market, so market needs to find a price point at which those BTC can be absorbed. Now the argument is:
1-who is more likely to sell most of mined coins, mega farms or your solo farmers?
2-And by how much? If it's by 1-2% does it really make a difference.
I think history shows that first miners were horders, and actually just did it as a hobby at a loss. So i tend to lean that mega farmers would sell more, but again how much does it matter? There will be 3600new btc today and someone will own them