This admittedly is a difficult question.
Stellaris was not ready for launch when it shipped, and it seems clear that the current development team has a very (if not radically) different vision for the game than its original designers.
It's well worth asking, at what point are you just trying to paint stripes on a horse and call it a zebra? When is it worth fixing Stellaris, and when should they simply cut their losses and announce plans for Stellaris 2? I don't have the answer, but it's a good question.
Or rather, not a difficult question if taken from a business perspective. What is "losses" here? Quality, the idea of a beautifully executed game, or simply
money? Does the game sales still increase significantly at each DLCs/patches, or is the game at the end of its business cycle? I understand that comment could be somewhat taken with disdain by players, but one has to remember Paradox is in the game to make money. They have to pay salaries, they have to bring cash in to be able to invest it as development cost of their next game - which might be completely unrelated to a Stellaris sequel, and that can also be written as a write off before being even released. And from the last hints we could read from the devs, Stellaris has becoming a best selling game for PDX, with the team being expanded.
One aspect of Paradox I like the most is that they have a great podcast series given from a business perspective (The business of video game on YT). It's a subject that is usually hardly well known or discussed about, and I'm personally grateful PDX share their insight here. And yes, it is sometimes really
blunt: I remember an episode where they discussed quality vs the constant changes demanded by their development model. The bottom line was something like "players have to adjust to the quality of the game, not the opposite" (don't quote me on that, I can't find the right episode right now but that was the gist of it). I was kinda feeling a bit offended by that comment in some way

, but then I realised that this is the reality of business.
From this, I think it is fair to assume a focus on polishing of Stellaris won't happen as long as features bring in significantly more sales. Small DLCs like portraits are good from time to time, but I guess PDS can't exclusively count on them on the long term either. And a costly focus on polish won't happen if they can work on a better planned sequel in a few years. After all, if the game sold well and players play it with the
current quality, then that quality is
good enough. The
bait of the development model is the promise of a "better game" in the long run - and in many ways it is true - but not necessarily one of better quality. It might not become a zebra at all, but at least the horse got some stripes - and a big pool of money for future development.