I'll contest just one thing: FO76 isn't having bad sales because it's a sorry, buggy mess (it is). It's because nobody cares for an online multiplayer Fallout. 90% (heck, I'm keeping it low) of sales come from the first few days of launch, just like movies make most of their gross income in the first weekend in theaters. That's why expansions (and standalone ones at that) or major DLCs became such a prominent business model as well, because on the market they work like little "re-launches".
We all saw that coming with FO76 a mile ahead ever since E3, but didn't stay away from it just because we expected it to be worse than your average Beth game, we did because Bethesda's playerbase (the FO and TES one at least) really is in large part a different demographics than the MMO one. They tried to pitch into the survival fad, but they were late to the party, very late, and didn't even had the right playerbase to at least count on selling on the name of the franchise alone (which happened for FO4, that was a disappointment for most even though, technically, in line with previous titles).
Remember that Rebirth was the best selling game for Egosoft. Their arguably worst game was the best selling one, even though no longer than 24/48 hours after release everybody in the gaming world knew it was one of that year's worst trainwreck releases (whether we personally agree or not it was their worst, half of the gaming internet made it a meme to make fun of, that was the common perception). People buy games based on expectations, not based on their actual real state. Which is bad (real bad, and preorders further add to that), because it allows companies to care less and less about the actual state of their releases. Some will then fix their game later, like Egosoft does (whether it's for passion or because they do it for damage control doesn't change the result, which is at least positive in the end), others won't, and those that won't, don't because they are confident the players will forget anyway before the next game and will come back with their brand new expectations and hype. And, usually, they are right, They don't guess, it's marketing "science". This, of course, doesn't always apply, especially on those franchises that churn out a game every year (Battlefield V is a good example), and sooner or later sometimes it will come back to bite them, but it takes a loooong time.
What's worse for the average quality of the industry between the two models? Feeding high, unrealistic expectations that more and more often get disappointed at launch, but still sell the game mighty fine (they wouldn't do it otherwise), and usually somehow getting away with it even though a lot of people - rightfully so - complain, at least for a bit... or declaring from the very beginning you'll launch an unfinished game, ask money for it anyway tagging it as early access, and as such lowering just as well the bar of what is generally considered a product good enough to spend your money on?
I honestly don't know: both models, in the end, lower the bar of what's considered acceptable, lower the value of your money. Sure, an early access could be considered "an investement" (albeit a very dangerous one nowadays), but then the same could be said of games like X, that still get developed long after launch, whatever the launch was labeled.
And, BTW, while X4 clearly is in an unacceptable state for a full release, this fact doesn't change and won't change because of a comparison, I've seen much, much worse releases, and much worse "false advertising" before. Do you perhaps remember Elemental:War of Magic? That game by Stardock - another rather little company that was (heck, still somehow is) very well loved by its niche much like Egosoft - that was supposed to be the new Master of Magic. It wasn't only such a buggy and empty shell of a game that taking the worst of X4 and Rebirth and putting them together you'd still have a CD Project Red masterpiece by comparison, but it was called Elemental and it didn't even had... guess what... elemental affinities! Yeah, fire does double damage to ice, basic things like that. Somehow they are still afloat, and even more surprsingly are still well regarded in the public's eye (even though now they also shat all over the Star Control IP), because the general public... forgets. Politics teach us that.
X4 is still missing some promised features, but most of what's missing isn't just *not here*. It's *in, but quite far from an acceptable state*. The war mechanic is there, even the mechanic to capture sectors. It's just it wasn't playtested basically at all, was jury rigged here and there with placeholders, and it all went at launch blind, fingers crossed hope it works, we'll fix it anyway on the go. Now, if they said that "all the races of X are coming back" and then we found out only three were here, then that would have been a whole different thing. But they didn't. They made the public aware well ahead only three would be in, and the others (some, all? Not even that was promised) would come later. Their marketing pitch was honestly among the less pretentious I've seen in cases such as this. Sure, the delivery still was arguably insufficient, and there's no excuse for that, but the game still has mostly positive reviews, so it's not so much of a wreck like topics such as this one usually end up implying.