The upside isn’t limited to £10m profit.
If he’s actually good enough to be, for example, a 15-20 goal a season striker then the upside can include European qualification and the money that brings, increased profile by having top attacking talent, increased opportunity to attract better players over the next couple of years by having a better team etc.
We do still need to have an element of short term thinking to keep us an attractive proposition. If Kean is who Brands/Silva is the best forward we can attract at this point, then I don’t think a buy back clause should stop us going for it personally.
Fully get that but it's still us taking the risk with a not insignificant amount of money that we could gamble better and I think a big part of me not liking it is that I feel this is a PSV style deal e.g angelino and we are Everton, not PSV who are happy to develop a quality young player then sell him for change.
But maybe we should be more like PSV, and like I say above, two years is more comfortable as we're not just back in the same position this time next year, we get 2 years of potential CL talent which I can live with.