You're working under the assumption that:
1. Ten Hag will be a success here or at City
2. Ten Hag is guaranteed to come here
And are you willing to waste an entire season and missing on everything in the hopes that Ten Hag will not only come here, but be the next Pep? That's quite the risk.
Well, not exactly. We waited for both LVG and Mourinho. LVG was contacted before the World Cup and he agreed to join us after. Same with Mourinho when he was sacked from Chelsea. At any rate, regardless of whether Mourinho or LVG failed here, they were smart appointments at the time. Obviously, didn't exactly work out, but the club had the right idea. Sticking with Ole is what got us into this mess. And of course appointing Moyes in the first place. These two grave appointments (Ole and Moyes) basically made us slog through a quicksand and all we've been doing since then is attempting to get out.