That 'experience, stability and youth' thing is a bit of a false alley, imo. *Every* team will claim the same thing. Every one.
Mourinho has settled in at United, his players will have bought into his methods, Pogba, Martial, Rashford and Bailly are all young and will improve.
Conte has settled in at Chelsea, his players will have bought into his methods, Zouma, Batshuayi and Alonso will all improve, and they have a bajillion young players they can recall to aid them since they will all have gotten better as well.
Pep has settled in at Chelsea, his players will have bought into his methods, Stones, Jesus, Sterling and Sane will are all young and will improve.
Klopp has settled in at Liverpool, his players will have bought into his methods, Coutinho, Firminho and Mane will all improve.
Wenger has been settled in at Arsenal for a long time, but Bellerin, Oxlade-Chamberlain, Iwobi and Holding are all young and will improve by dint of experience and a winning mentality brought by their FA Cup victory.
Koeman has settled in at Everton...
...you get my point. It's not that such an effect doesn't exist, only that it doesn't exist in a vacuum, and that others have the same reasons to expect the same improvement as we do. So, really, it is standing still relative to everyone else - worse if, as I said, we swap WHL for Wembley, which will definitely bring wobbliness we didn't experience at the Lane last season.
I certainly don't think we won't sign *anyone* - it's becoming increasingly clear that we're going to be pretty much forced to be the last in line waiting until August and everyone has had their fill of the available talent. Then we can pick from what's left - and, possibly, we might have to wait even longer before moving as even clubs our size (Roma, Dortmund, Sevilla and co.) pay wages we won't and get players we can't. That seems like the pattern we're going to be forced into, and there are positives and negatives to such a reality - but it certainly doesn't mean we won't sign *anyone at all*, per se. But I don't think we can get away without signing anyone and expect a significant improvement on last season, or even an on-par season. So while we may have to wait, and that's acceptable, I think ending the window *without* any movement would be a bad move on our part.
As for Chelsea's weak squad, I disagree, because they have the aforementioned bajillion players out on loan that they still pay wages to and can recall if necessary, many of whom are at or above the level of our comparable squad players (Andreas Christensen, for example, is probably better than Wimmer, Mario Pasalic was on loan at AC Milan and became an integral component of their midfield last season, and Marco Van Ginkel has accumulated more multinational experience than the majority of our squad while being a consistent loan ranger). Yet, they're going for the more expensive option of beefing up with first-team players good and early, which indicates more than just filling squad gaps, imo - it indicates a desire to improve and not stand still on their part.