If I had £30m to invest, I would sack RK and offer Curbishley a lucrative contract to prove he's not a one club wonder and then give him £10m in the transfer market to make it happen. Harsh on RK but I don't know whether he'd deliver. If we got promoted within a couple of years and then invested again when promoted, how could you lose money as long as you found someone to buy the club at it's new valuation?
But what happens if he fails?
Lots of clubs have spent money trying to get out of this league and found it harder than they think.
If he spends money on new players with expensive contracts, employs an expensive manager (although I have no idea why you think Curbishley will come here), and we end up failing to promoted, what happens next?
Does he keep putting money in until he achieves success (assuming he's got the money), or does he get out and leave someone else to sort out the mess he leaves?