You are misunderstanding my argument.

When you use up negentropy, it is used up for good, and there is a finite amount in each section of the universe. The amount being used on Ishtar could theoretically support good lives of billions of upload minds (or a smaller but still huge number of other possible lives). This isn't a matter of a long and narrow future or a short and wide future, but of how many total, worthwhile lives will exist.

As for quality, there seems to be no reason why simulations can't be as happy, or even happier than Ishtar.