I wonder how an outcome could look where the "naysayers end up being mostly right". I guess you refer to a possible wave of spam via big OP_RETURN data transactions.

But is this a realistic outcome? We have to take into account that the limits increase does not create additional incentives for data transactions, because there are already cheaper options like the Taproot "exploit". And the Bitcoin Stamps method is almost as cheap as the OP_RETURN method (but much more harmful to nodes resources).

Then all what's left for such an outcome is a "social" effect, i.e. some people could think that "Bitcoin" now "approves" the usage as a data storage and thus are more comfortable using tokens or NFTs based on OP_RETURN.

I guess however this would be an extremely weak effect. Because the big "spam" waves like Ordinals Inscriptions benefitted from scarcity. If you created a big NFT paying a lot of fees to a miner to mine a non-standard transaction, then if this type of transaction became "standard", this would lower the scarcity and thus the price of the NFT.

An example: A couple of pages ago a new OP_RETURN based "non standard token" protocol was mentioned. The "scarcity" of these tokens due to their non-standardness (and thus the potential re-selling value) was one of the promised "features". However, with OP_RETURN limits lifted, this would mean that many nodes could treat these tokens as "standard" and thus it would be easier to create them. In the long run this would lead to less of these transactions, because they still cost fees but lack any "scarcity".