The former obviously, despite some old-core toxic players - like Pique- still having leverage to start games.
Depends though on next season.
The first phase of rebuilding should be followed and built upon, rather than going on different direction.
Hence not Xavi or other experiments.
Koeman to continue and to be given more authority on ousting seniors.
Next summer hire a WC coach that might be available to take it to the next level
What makes you think Koeman even want to get rid of the senior players? He could have decided to bench and not play Pique like Lucho did. He could have decided not to insert Sergi Roberto into the lineup as soon as he became available, yet he did.
He could have decided to tell the club to sell Coutinho last summer, but he didn't because he saw him as essential to his project. Not my words, but Koeman's and Coutinho's. Not to forget he actually told Pedri he should have gone on loan too, but the club intervened and kept him because they didn't sign Wijnaldum as Koeman wanted.
How can you say with confidence that Koeman is the right man to start a fresh project?