There are a few different aspects that could be gone into at length.
NUFC has to have certain accounting standards that also fit in with the football authorities and Financial Fair Play. There were some things that Freddie Shepherd could not do now. As for his retail business, he has difficulty with his auditors but would lose a bucket load if he tried some of the same things at NUFC.
Something to understand about Ashley is that he doesn't draw a salary from any of his businesses. Where he gets his pocket money from is dealing, so capital growth.
As for relegations, sure he has made short term losses but in the overall context, has been able to reduce his tax bill with other enterprises.
His core loan, which has to be repaid at some stage if there is a takeover, is £111 million. The relegations involve switching money from one piggy bank to another and back again later. However, note that from the cash situations, transfer cash surpluses were generated under Hughton and Rafa, at least in the medium term since some players were sold on instalments.
As for how Ashley views his asset, TV revenues mean that the value of clubs has gone up in line with TV money. He is sitting on a potential profit of £250 million, if he plays his cards right, a hell of a lot more, if he doesn't, about half of that as things stand.
At the end of the day, he will do what suits him at the time.