What makes you think that it’s necessarily the “casual players” who are spending ISK on PLEX to feed their accounts, and that the veterans are the ones buying PLEX from CCP to trade for more in-game stuff?
Why can’t it be the other way around, with newer players taking advantage of the high value of PLEX to get a head start in the game?
Your conclusions are predicated on a custom-tailored reality that you had to construct in order to make them valid, instead of one naturally determined by data and empirical observation.