It has been recognizable since 2017 but without the polarizing debate, the PLQ and PQ have nothing left to offer. PQ is destined for the dustbin, and PLQ would be joining them if not for the Anglo seats, where voters are still leaving the party.
And what has constrained the Anglo-seat exodus is that there's no clear, palatable alternate option unless CAQ became an even bigger tent entity than it already is (i.e. the one that Dominique Anglade ran for a decade ago). PCQ's too far right except maybe out Pontiac way or if they made inroads w/certain ethnic groups like (echoing recent federal patterns) Orthodox Jews, while QS is too far left/too post-PQ for anyone other than millennial cosmopolitan hipsters. Thus you'll likelier get D'Arcy McGee type polling as per Mainstreet: still solid Liberal by default, but no longer "North Korea" giga-solid. (Which actually might be a healthier state of affairs, electorally speaking.)
If you wanted to be
really trollish, you could say that Québec's party system is actually converging on Canada's federal one, just adjusted for local sensibilities. The CAQ as the Liberal analogue squatting like a toad across the political spectrum, the PCQ as a post-Harper CPC-esque hard-right awkward squad, QS as Singh's NDP sitting on the sidelines forever, never quite reaching the voters it says it would like to reach, and the PLQ as the Bloc, having shed its air of invincibility but still able to represent a section of voters that possibly can't be durably integrated into any other party's coalition without causing friction elsewhere.
Obviously this is a very reductive and cartoonish analogy, and you could poke plenty of holes in it, but it might just suggest one possible future trajectory.
