No, it means that player mature in their game and after years of experience get better and better in in dictating play, dictating tempo and improve tactically. Especially in that role, how many young midfielders play that "quarterback" role, it comes with time.
Bakayoko is bought as a replacement for Matic, plays in the same or similar position as Matic, whether stylistically they are the 100% same players or not, Bakayoko can well prove to be a better player for them in the longrun than Matic was for them. I am not sure how you say he will never reach his level of composure as if Matic is the midfields Messi.
Drinkwater is Matic replacement. Bakayoko was to add to Chelsea team regardless. They don't have that depth and it has been proven with Kante out injured and Drinkwater still not fit to play. Cesc and Bakayoko haven't been assuring.
Strange question to ask. It seems like some high profile transit role make people think the deep midfielder role is a role that every majority of midfielder would eventually master. For every Kroos, Modric, Scholes, Pirlo, Matic, Bastian... you have abundance of deep midfielders would stay and develop how they initially broke through. De Rossi, Thiago Motta, Busquet, Xabi Alonso, Van Bommel, Xavi, Casemiro, Emerson...
As pointed out in previous post, those who were able to make the transition in role, always showed a good playmaking, vision... from young age in different role. The way you look at Bakayoko to develop dictating play, tempo... is like expectation of Rooney to become another Scholes. Rooney was explosive players. He may have good passing technique to pull some Scholes esque pass, but always a sky apart in term of play making ability. Reality proved just that point with Rooney failed miserably transited to a deeper role.