Pochettino knows that he is going to be forced to just develop the team gradually, one by one, step by step. But the owner is spending so much money on the team so he wants some results right away. In football world you do not get results right away, that is just not how it works at all, you do not end up with good players and good situations all the time, you just end up with getting better with time.
But, the owner is some rich American, of course he doesn't understand how it works. In their world, they could spend money to some sign stars at Free Agency and then be a good team, so he looks at how much players at America makes, and how much they are spending on transfers here, and he thinks that they should have some awesome team.
In football that is not how it works at all, that is why I prefer INEOS approach, they are spending more clearly and cleverly now, and that means that we are going to see United do much better than Chelsea. Both were taken over by their owners around the same time give or take, but United has done better because they know it will take some time, so they focus on great young players that have good potential to help them on the long run to gradually become better.
But I think Manchester United and Chelsea are two elite teams that are still equally difficult to get good results, so I can't distinguish the success of these two teams in recent seasons. After all, if for example Manchester United failed to win the FA Cup trophy too, the reality is that Chelsea managed to get a Europa League ticket. But yes, because Manchester United managed to get the FA Cup trophy by beating Manchester City, then Manchester United won the Europa League ticket next season.
But anyway, I think Chelsea and Manchester United are also still both building teams with their young squad. And thus, then of course they still need a long process to get good results with a young squad and new ownership. But unfortunately, Chelsea is very too hasty in buying players and also firing coaches and thus, it will still be difficult for them to get the results as expected.