No. But if the maintainer is burning out and doesn't have free time available for it, paying them so they can take time off to actually work on the thing is a nice way of fixing issues.
Not everyone can take time off from their day job just because somebody paid them a nominal amount of money.
Besides, the maintainer in this case was already taking time off regularly, not to work on xz, but to get away entirely from any kind of programming work. Throwing money in his general direction probably wouldn't have helped with the burnout, unless you were offering to help him hire somebody.
The more money we give, the more viable it becomes for maintenance to become their day job. It's very likely that more money here would've mitigated the burnout. Aside from just being able to quit their actual job and focus on their passion project, it's acknowledgement that the world finds this work valuable. In many cases, burnout comes from a lack of recognition, or the sense that you've done all this work and nobody really cares.
You have it backwards: The notion that open source developers can not or should not ask for monetary compensation for their work is what leads to their exhaustion and their project's demise.
Of course if the developers don't want to be paid, then that's that. But otherwise, there is a very heavy atmosphere in the open source community of excommunicating anyone who dares to ask for payment as heathens of the vilest order.
> there is a very heavy atmosphere in the open source community of excommunicating anyone who dares to ask for payment as heathens of the vilest order
I fully agree that forcing payment or using dual licensing is unfortunately heavily frowned upon. But a voluntary Patreon/donation option is perfectly acceptable to the same anti-payment people.
Besides, the maintainer in this case was already taking time off regularly, not to work on xz, but to get away entirely from any kind of programming work. Throwing money in his general direction probably wouldn't have helped with the burnout, unless you were offering to help him hire somebody.