That makes sense and I've also heard that passengers who don't cancel dining reservations in the restaurants that require a reservation amplify the problem by taking reserved but unused tables "out of commission" resulting in more passengers being funneled to the open seating restaurants.
I also wonder whether the shift away from "social" tables has exacerbated the problem. For many years, when you entered the dining room, the Maitre 'D would ask if your party wished their own table or to join a social table. We'd often join/form a table of 6 or 8 and always really enjoyed that aspect of Silversea - met so many interesting people that way.
That option went away during the pandemic and I was chagrined to find on my last two voyages on Silversea that it really hasn't returned. When I asked to join a social/shared table on the Spirit and the Nova, the Maitres' D each said they don't really do this anymore.
Pragmatically, this shift also has the effect of reducing the number of parties that can be served in the dining room at a given time if 2 or 3 couples who might previously have dined at a shared table now dine as parties of two or joining one other couple.