You bring up some important points that I need to clarify for everyone:
One reason I've been holding off on buying Odyssey is that it's much better to download it after Frontier has applied a month's worth of patches and hotfixes rather than trying to do anything with it while it's actively being patched. Otherwise it's like working on a Google Doc where two people are typing in the same paragraph at the same time. So even if people were to donate to the "Old Duck Odyssey Fund", I would still likely hold off another month before actually purchasing Odyssey.
As for ease of modding, my latest mod includes a ton of custom shaders, and that is what will be difficult. Replacing hashes of shaders that are just turned off might take me an hour, but modifying a single shader to improve one little graphical oddity might take all day, and there are dozens of shaders I touch in Horizons.
The other thing I want to be very up front about is that I'm not poor. I can afford Odyssey. I just don't want to give Frontier my money right now, partly because I don't want to reward bad behavior, but also because of what I mentioned above - I'd rather wait even just a month for Odyssey to be patched so I'm just downloading ONE update instead of dozens. So if people really want to gift me Steam cards (not much different that Patron for Youtube content creators, I guess), I'd probably put those towards Space Engine or some other game, and then later I'd just use my own money for Odyssey.
So in other words, if you're thinking "Duck needs Odyssey today, so I'm going to help him buy it", that won't work, because I fear downloading Odyssey today will be more trouble than it's worth even if it were free.