I'm not saying United were an underdog when Mourinho took over, I'm just saying they were more of one than Spurs currently are. In the three seasons before Mourinho's appointment United finished 7th, 4th, 5th and won the FA Cup. In the last three seasons under Poch, Spurs have finished 2nd, 3rd, 4th, and reached the Champions League final. The level of expectation at Spurs might not be the same as at United but Spurs are still currently better placed to succeed than United were in 2016.
Anyway, this is getting away from the point, which is that this is a horrible appointment by Spurs and just about the worst decision Levy could have made to patch the team back together after a difficult spell. We know how this is going to go: Mourinho will probably win one of the domestic cups in the next two seasons but will leave them considerably worse off in almost every department, before leaving under a cloud with a massive payout. He's done the same thing at every club he's been at since forever - why would this go any differently?