Their only concern is whether they can extract their dividends. They can still do that so the sacrifices will be made elsewhere - less to spend on players, no funds to improve the stadium etc. On top of that, United are a >£3bn asset against which they can use to leverage their other business interests and investments. Remember, the Glazers don't buy anything with their own cash.
Anyone who thinks they wont run us into the ground is, in my opinion, deluded. How much of the clubs value is leveraged elsewhere? We dont know, but the reality of a sale for them might not actually pocket them as much as you would think.