I think they have hit a plateau where they have lost the opportunity to take a major domestic title thanks to City and Liverpool's (re)emergence and have underperformed in Cup competitions which has limited their ability to really progress in terms of mentality, and the associated benefits success brings. They are currently little better than the other three also-rans (Arsenal, Utd, Chelsea) but still have a somewhat undeserved aura of a 'Pochettino team' in pundit-land. Clearly there has been a disconnect between Levy and Pochettino but the squad situation is creating a perfect storm where there are too many important players performing well below capability, and Pochettino is at least temporarily unable to get the best out of others (i.e. Alli). In many ways, they have hit the same plateau other emerging sides come up against: Wenger's Arsenal, Klopp's Dortmund etc - although without being able to back up their rise with absolute success before coming to a point where some of the stars look to want out.
One of the oddest concepts in football has been the 'power shift' in north London. Spurs have been at a several-decade zenith under Pochettino, whereas we have - let's face it - been **** for a while. Yet in that timespan Arsenal have put as many FA Cups in the cabinet as Spurs have won in over 50 years and reached another two Cup finals. What would you take? That's not even a critique of Spurs, but just another example of football's propensity to over-celebrate and likely now over-criticise.
The upcoming months will be interesting. Spurs don't have the resources to compete at the very top-table, the Prem is already a distant dream, and they are now reliant on a Cup run to try and galvanise the club. Pochettino needs to find a way to re-energise the squad and somehow begin to replace the likely outgoings with quality. But does he have the energy for it himself? He must acutely realise his window of opportunity to land a top job is narrowing.