Maintaining price consistency does not indicate a paradigm shift away from other altcoins. If that were happening, then they should have gone higher than Solana and Ethereum when those coins were pumping.
Of course the "shift" hasn't happened still ... that's why I wrote "incoming".

For me, such a paradigm shift would come in waves. The first wave would be what we may be experiencing now (or not) ... a rather stable behaviour in uncertain bearish times. A second wave could build on the first one, and there we would then probably see both coins return firmly in the top 20 or even top 10. This would be the confirmation for the shift.
But this is kind of nit picking. It is not accurate to compare Altcoin performances in such short timespans to how Bitcoin performed and call it an incoming shift.
I'm comparing them with other altcoins' (bad) performance in the last weeks, not with Bitcoin. It's of course more likely still that it's a simple coincidence that both coins performed relatively well. For example, Tron also was among those "performing well" and is a fairly normal PoS coin, as is BCH (imo an edge case, neither the most scammy nor the most solid project, I personally don't like it).
However, I see the possible "shift" in a broader context. Solana was the most hyped coin in the last year and now it has basically returned to where the hype started. Ethereum is also performing weakly. And memecoins could have hit the top after the Argentine Crypto-Gate with $LIBRA and the TRUMP token. In contrast, XMR and LTC were underperforming last year but now are returning into the top positions again.
With the rest of your post I agree -- if we take into account that XMR was delisted from a lot of big exchanges and then its price recovered without problems, the outlook for Monero looks quite bright, and privacy at Monero's level is something very difficult to achieve with BTC, even taking into account CoinJoins and Lightning.