8% of their users? as in the fees they get? So this is almost an irrelevant fraction at current fee market.
But we'd also have to ask what percentage of users will be lost in a BIP110 main chain scenario. No more jpegs and other spam, right?
Recent research indicates that revenue from spam accounts for about 0.1% of mining revenue: https://blockspaceweekly.substack.com/p/issue-7-why-miner…
So I would not be surprised if 8% of active "monetary maximalists" already outweigh that, and outweigh it even more if more of them start running BIP110