Here's why this is pompous:
* Unnecessary jargon: "Inordinate," "frivolous," "deplorable," and "intellectual" are more complex words than necessary. The sentence could be clearer and more concise using simpler language.
* Overly formal tone: The sentence uses formal language that feels stiff and pretentious.
* Self-important language: The language suggests that the speaker is superior to the "average citizen" and is criticizing them from a position of authority.
A less pompous way to say the same thing:
"People have so many ways to entertain themselves these days that some people may not be reading as much as they used to."
This version is clearer, less formal, and avoids making judgments about the intelligence of others.