I didn't have the interest or financial means to focus my capacity for obsession on audio until about 15 years ago, so I never got as far down the rabbit hole as I might've been, had circumstances been different.
At this point, I'm approaching the end in terms of feeding the desire for better and better SQ.
My system, in its present state, is "good enough". Significant improvement in sound-stage depth was the tipping point for me and ironically, I didn't have to spend a cent to achieve it -- I just played around with speaker positioning -- call it my "last gasp" of obsession :o)
I find I no longer enjoy being obsessed. Chasing "better" is inherently a state of dissatisfaction -- a sort of "nagging emptiness" demanding to be filled. While I once experienced this state as enlivening, now, it just feels exhausting. To be fair, I do have a tendency for OCD. Those in this hobby who are not so afflicted may not relate to my sense of relief associated with withdrawing from "upgrade fever".
Given the above, I'm grateful that I couldn't afford what it would cost to take my system to "the next level" and that, even if I could, the fact that my listening room is my living room would inevitably constrain the return on such an investment.