IMO you can snag less corroded boards off eBay or Pinside fairly cheap a lot of times if you're not in a huge rush and don't mind a little bit of work. I've had people give me free boards a few times that had some small amount of corrosion that hit the 5101 socket and that was it -- just because they put an aftermarket MPU in their machine and the old board had no value to them. Not really a need to buy $150-200 board if you're comfortable doing some work yourself because of how many people are in the same situation without soldering equipment, replacing a board that has lighter amounts of corrosion and selling or giving away the old.

Bottom line is, markets change as cheaper options become available and people value their time more. So cheaper aftermarket MPUs = greater likelihood of finding less corroded boards that are easier repairs.

Fully agree with others, that board isn't worth the trouble. Keep your eyes open, or post a wanted ad for MPU boards with light amounts of corrosion. They're a dime a dozen and most people would probably let 'em go for under $50.

Just my 2 cents