I would argue that if we get abundance before fundamentally changing ownership structures, we will get a handful of people that control said abundance and with that, have basically infinite leverage over the rest of humanity.
Labor will no longer be required for their productive needs, so that handful of people that controls the abundance machines will no longer have any incentive to keep the rest of humanity satisfied, or even alive for that matter.
In other words, if we don't change social relations before we get to this state, we will end up in a world where the Musks, Bezos and Zucks of this world control all material production, with the rest of us reduced to being dependent on their charity.
Personally, that sounds like the worst dystopia imaginable.
I will give you that prior attempts at socialism weren't necessarily successful and a lot of people died, however, I also think that argument requires holding one eye shut.
People are dying from capitalism right now. There's a homeless guy in SoMa that is breathing his last breath as we speak. There's entire villages in Africa that can't afford clean water while Nestle sells it in plastic bottles that pollute our planet. The status quo is not without its own violence and I think that is a point that too often gets swept under the rug.
Either way though, I think even if I were to concede that capitalism historically had better outcomes (which I have not been fully sold on! it's positives have just been more articulated imo, but that's another debate.), we are in a critical moment right now.
If we really believe we're to transition into a post-scarcity world, we need to make sure the right social relations are in place before that happens and whatever we have right now is locked in forever.
All criticism of socialism's supposed productive ineffectiveness becomes irrelevant once the transition is done anyways.