I think Ubuntu is a for-profit company. I think System76 is a for-profit company. As a rule, companies tend to respect other companies in ways they don't respect people.
I think it's more likely that System76 will rebase to Debian than Ubuntu kick them off, but if Ubuntu really starts pulling out the brass tacks, I don't think System76 will show any loyalty.
In other words, I think Ubuntu benefits from counting all the Pop!_OS users as part of the Ubuntu family (at least statistics wise), that they'd be killing a golden goose by trying to evict them, even though they'd obviously prefer them to use Snaps.
This hurt to read. Thank you, I think…