If what's being said is true then you'd have to sympathise with Mourinho but it really doesn't look like the purse strings are that tight. You don't need to spend £90m on Pogba's and similar on Lukaku's to secure top 4.
Well considering Ed wouldn't get Peresic over the line in the summer because he was too expensive suggests otherwise.
Since before Fergie left the majority of the time the squad has rarely had a proper 1st XI, Utd have had 3 or 4 big stars and the rest are pretty average squad players.
There are always going to be transfers that don't always work out, and that's the nature of the beast but when you only get 3 or 4 purchases done every summer (and rarely anything in the winter) that's only going to allow for 2 or 3 new additions after you have replaced the one that didn't work the summer before - or even the summer before that. Moyes buys are practically non existant for the last 18 months, and LvG's that are still here are average at best. That's even before some of JM's transfers which have been a bit hit and miss also.
A club the size of Utd is never going to have the squad quality required from the starting position Fergie left it in with that number of transfers every year.
Admittedly the injury crisis we appear to have every season doesn't help, even after investing millions in the medical equipment at Carrington in the last couple of years.
I'm not expecting 6 absolute ready-made superstars every season - but the way the squad has turned out for the last 6 years, 2 - 3 ready made stars (or at least ready to step into a senior role), and three more that might need a year or two to come to fruition is desperately needed to compete right at the top. Even if that means retiring / selling the same amount.
edit
In reference to top 4 - if Liverpool are spending £75m on a centre half, even before considering anything else they might do in Jan (and they weren't that far behind us in the 1st place) , Spurs despite their blip in Nov have a very good well rounded squad, and Chelsea are fighting us already tooth and nail for 2nd (and rumours they will bring in re-enforcements also) and they didn't spend that much less on Morata in the 1st place.
Its really not inconceivable Utd need at least two if not three additions to be ready to go immediately to have a chance at top 4 - and players ready to go will always cost more than prospects. (unless the club finds out of contract players, but they are out of contract for a reason - and therefore a different type of risk).
Its better than it was, but of course it doesn't help that Utd are still paying £45mish a year on the Glazer debt