There's nothing weird in infinite expansion. The expansion is in utility provided. Making and storing a good movie, a game or a book doesn't consume much energy or resources, except that needed to sustain the human makers, which exist anyway.  
There indeed are theoretical thermodynamic limits to this (Bekenstein bound), but they are so high there's room for millions of years of growth.  

Utility gained per marginal energy unit is dropping for decades now. Eg. there are physical limits to how much food a human can consume.  

In the future per capita energy use will probably drastically decrease, at the same increasing the quality of life. Outside of obvious things, like increases in efficiency, consider improvements to humans themselves. For example, the eye - what would happen if everyone could get an artificial eyes with much, much higher light sensitivity? Energy expenditures for lighting would drop by orders of magnitude and never recover.