Ok, so would you prefer to pop all but 7 humans out of existence (assume that the process is painless) in exchange for the remaining humans experiencing Ishtar level happiness?

If you just mean to say that terminal values are arbitrary, so some possible minds might prefer the Ishtar scenario, then that's fine, so far as it goes. But if you take multiplication seriously, then its insanely hard to make the case for this being a genuine eutopia.

Isn't it equally tragic that in the real world the resources that are currently maintaining my life aren't instead being used to support other, more worthwhile, lives?

My argument isn't that each life which might have been is more valuable, but that they are when added up.

First of all, uploads aren't yet possible, so far fewer lives worth living could be supported with your resources in the first place. More importantly, since most resources aren't being centrally distributed by all-powerful machine gods, we would have to tax your earnings. This involves the infamous "leaky buckets" problem acknowledged by all utilitarians. People engage in tax avoidance behaviors, work fewer hours, hide income, and some money which is captured is spent on overhead. These problems don't exist when all resources are being created and distributed by a central depot.

Furthermore, the ability to actually get those resources to the people in need are in doubt, due to grabby governments/warlords/logistical problems etc.

But yes, overall I would say it is tragic that some of our 1st-World resources aren't going to save marginal lives.