Thing is, who is available who'd really improve us? I'm quite happy with what we have and wouldn't mind being patient to bring in more quality next summer. Seemingly we were never interested in Otamendi, missed out on Sergio Ramos or never had a chance and don't have that many options left for central defence. I still rate Hummels highly and he'd probably be perfect in van Gaal's system, but apart from him there's not that much quality left. As for young players, Laporte and Stones need games and I'm not sure if they would solve our issues or would improve us that much yet. They're obviously very talented, but it seems it would be better for both players if they stayed put and we used what we have.
The same probably applies to forwards. No one of Benzema, Lewandowski, Müller and Kane is really available. Lacazette doesn't seem to fit the profile of van Gaal. There are quite a few talented forwards out there, but again, they'd probably be better off with staying where they are and we couldn't make much use of them anyway.