I think Chelsea are great at buying players but their unstable management often means good players fall out with them.
People are pointing to selling Salah, KDB, Lukaku etc. but lets be honest here, those were absolutely brilliant players they scouted, bought cheap and then Mourinho kicked to the curb in pursuit of a short term gain.
If Lampard's very close personal relationship with Abramovich and his unmatched popularity with the fanbase give him stability they've not had before, they could be getting a similar group of talents together to circa 2012 under a manager who won't cast them off.