When we look at experience itself, there is no fixed “I” to be found.

Speak for yourself. That whole paragraph does not resemble my experience. You recommend Parfit, but I've read Parfit and others and remain true to myself.

When we look at experience itself, there is no fixed “I” to be found. Boundaries between self and other aren’t innate to reality but drawn after the fact. We carve up this vast space of experience into “mine” and “yours,” but these divisions are somewhat arbitrary.

The boundaries are somewhat arbitrary, but it seems to me that if we keep going in this direction far enough, at the end of the road is equanimity with the universe being converted to paperclips. (Which would be a wrong thing in my current unenlightened opinion.) After all, there is no sharp boundary between "me" and a paperclip.

If resources and opportunities are not perfectly distributed, the best advancements may remain limited to the wealthiest, making capital the key determinant of access.

Largely agree. Nuance: Instead natural resources may quickly become the key bottleneck, even more so than what we usually denote 'capital' (i.e. built environment). So it's specifically natural resources you want to hold, even more than capital; the latter may become easier, cheaper to reproduce with the ASI, so yield less scarcity rent

An exception is of course if you hold 'capital' that in itself consists of particularly many embodied resources instead of embodied labor (with 'embodied' I mean: inputs had been used in its creation): its value will reflect the scarce natural resources it 'contains', and may thus also be high.