It is definitely true that any license including the GPL requires effort and resources to enforce, and that almost all authors of GPL software don't have enough of those.

If the SFC lawsuit against Vizio succeeds, then there will be another option; since yourself and others are third-party beneficiaries of the contract embodied in the GPL between Linux kernel developers and hardware vendors that ship Linux; start a class action with other users of the hardware where GPL violations are present, and sue for GPL compliance instead of money. The lawyers will get their legal costs presumably and the users should get source code. Probably some law firms would take this on just for the legal costs, especially if the Vizio precedent makes it easy to win future cases.

https://sfconservancy.org/copyleft-compliance/vizio.html

PS: I don't think SFC have an endowment, they are just directly funded by people who support their goals.