The way I take it is that Liam Howlett started out making something that transformed his influences, and then regressed into making something that sounded like his influences, more or less - in both cases he was riding the zeitgeist and raking in the cash, it's just that the zeitgeist was going backwards. Also by 1997 the Prodigy was a brand based around band image, so the music was second fiddle to Keith acting 'crazy'. But yeah, Oasis is probably the main part of the answer.
wow haven't listened to prodigy in ages is the early stuff really that good compared to most london hardcore i used to love that album experience but will i like it today i don't know.