Top shelf work would have involved selling one of them already for huge money (a la Coutinho or Hazard) and reinvesting those funds to build the next team.
Right now they’re just treading water without either putting together a team that could seriously challenge for top four or seriously laying the foundations for the next team.
The current team under Nuno has the same basic problems that Spurs did under Mourinho. Their players in the back and midfield just are not good enough with the ball to control matches and play with the ball except against teams that sit back the entire time. Fight them aggressively and they just cannot keep and advance the ball. Even teams like Palace and Brighton have been able to completely stifle them.
It will take major surgery in the transfer market to correct this issue if they ever want to get serious about it.