It doesn't matter how active Chelsea are in the transfer market and how much money is spent because it is the result and the performance on the pitch that will be judged. Because if a budget of that size does not show significant results, Chelsea will automatically receive a lot of criticism, including a failed coach.
Chelsea spent close to £600m last season and the impact was not felt they ended the season in one of the worst positions that made them lose out from all European competition. The club is already facing some backlash for their recent performance but it is just too early to start judging the impact of their new signings. If it is quality players, the club has them but it needs to show in the performance of the club.
Pochettino was challenged to build Chelsea from scratch after several coaches failed. So the question for Pochettino is whether he is able to complete the task or is he not able to do it but is still forced to do it.
I don't like Pochettino's coaching style. He likes buying already-established players. I will not be wrong if I assume that he depends on big names to win trophies. I am more comfortable with coaches that build young players. Coaches that groom unknown players to superstars are the best in the world.