Perhaps it is because he has kept us in the top 3/4 throughout that time with about the same resources as Burnley (in terms of net spend) in comparison with the other clubs? That and the fact he got to a champions league final only a few months ago. Not every club can be a Liverpool or a City and have those kind of resources. Ignore the bigger picture if you want but your argument is simplistic in the extreme.The season Pochettino took over Spurs they finished 6th with 69 Points with Vertonghen, Lloris, Eriksen and Kane in the squad (ahead of Manchester United).
In Pochettinos 5 season in charge of Spurs - they got 64, 70, 86, 77 and 71 Points - now that is an average of close to 73 Points. During this time they have won .. nothing. And they still have huge gaps in their squad (especially in defense). The fact is - if you look at the Points and table position, they have improved - but not much apart from that one season in 16/17
To all you wanting Pochettino - why ? What is it he has done that makes you think he is the right person ? He has had 5 seasons and they are not gonna be anywhere near Liverpool or City this season either. Not even Close!