Surely that's a question that every football club owner must ask themselves based on their own financial situation and ambitions, not a fan, but I'll try using an analogy in my own business life.
I've owned a small IT business for 16 years and I also worked for a large FTSE 100 company at a senior exec level, and at some stage in most financial years I/we had to make a (comparatively) large financial gambles and push the boat out. I/we had to invest in training, IT systems, property, transportation or maybe paying extra for quality staff as we are discussing now, but there was never any guarantee that we'd reap the benefits as you rightly say. Sometimes it doesn't work out, a new multi £million IT system didn't do the job and set us back 2 years, and in my own business, an engineer that I took a gamble on cost me a contact worth £thousands. Fortunately though failures were rare, and doing nothing wasn't ever an option because the competition aren't standing still, and customers want the best service they can get.
In the case of United, we're not talking tens of £millions like we are seeing across the city are we, so what would be a gamble our board and owners? How do you define your what is a 'small gamble' for a pair of muti-millionaires who I assume want to finally see this club back in the Championship and reap the benefits. Would £250k be ok but £1m way too much? How do we know what's right and reasonable for them and the club?
What we do know that Wilder has proved his worth, and on a fraction of the budget of his predecessors. We also know that we are currently in a fantastic position to gain promotion and 'all things being equal', bringing in better quality should result in us getting better results. It comes down to how much we trust in own judgement and our managers in this case Wilder and his team. We can't legislate for players getting injured like Samir or not performing, but just because we've made financial mistakes before as we did with that idiot Adkins, it shouldn't stop us doing what is right NOW. United are fortunate to have a fantastically loyal customer base that most businesses in the real world could only dream about, but try telling we the paying customers that the board didn't give Wilder what he wanted to finish the job just in case he failed again like all the others. I can only imagine the outcry.
So in answer to your question, based on what Wilder has done and shown with less and where we are now, if I was a multi millionaire joint owner of the our club, I'd take everything onboard and IF Chris wanted to push the boat out on a player I'd back him to a £million+ provided he thought that the player was good enough to make the step up, and young enough to be a saleable asset going forward. Sometimes you just got to bite the bullet and trust your instincts. The ghost of Dean Hammond shouldn't haunt us forever. UTB.