If an opponent tells me that owning an "Overlord's eXpansion" is too expensive for them and the issue is purely financial (given that everyone has different circumstances), I'm willing to buy it for them.
a clear and reasonable solution that can be applied in 100% of cases.
You might do that, but someone else might not only refuse to do so but also write on the forum something like "here we go again..." and keep bringing it up for the next two years, regardless of the context.
So, sorry – your personal willingness to go the extra mile for your opponent is unlikely to help the overall cause.
However, if you (or someone else) are willing to help the tournament as a whole (and not just this one) without unnecessary fuss (this doesn't preclude public expressions of gratitude), I know how to organize it. Write to me in a private message, and we'll discuss it.