A computer isn't a perpetual motion machine. It runs under the laws of physics just as everything else does.
How much energy do you think you would need to truly simulate a galaxy at quantum levels of resolution?
But what if you don't need quantum levels? Then you're into a more subtle argument - confusing an economy of resources with an economy of experiences that can be created using those resources.
It might seem "obvious" how that makes it possible to use less of everything, but if you think it through in detail it really isn't. You still need practical infrastructure, power, and even if everyone is in VR 24/7, you still need nutrients and waste disposal.
You can't start by assuming infinity because Moore's Law, and then pretending it makes all the hard problems go away. It doesn't.
The point is, if you can be millions of times more productive with the same quantity of resources, your reserve of economic growth is gigantic. Not truly limitless, of course, but limitless for all intents and purposes.
There is a lot of energy out there and a lot of technological growth to go before we hit a "finite" limit.
Imagine if moores law continues going strong, until we have computer's powerful enough to simulate realities. Now anyone can have whatever they want, only limited by computer processing power.
Also, just becuase resources are "finite" doesn't mean we are anywhere close to the limit.
You could just as easily respond by paying "Sure, the universe is finite. Let solve inequality by limiting the amount of resources a person can use to 1 galaxy per person. Nobody needs more resources than an entire galaxy!".
Until we get to that point, we aren't anywhere close to "finite" growth.