In the exact sentence you've given as an example, I'd use slump
Slump: to move down or forward suddenly
Slump: a marked or sustained decline especially in economic activity or prices
Humanity slumped into a materialistic society
It gives the impression of an untended stack of stuff that just randomly toppled into a mess one day.
If you want something more active, you might try bumble.
Bumble: to proceed unsteadily
Humanity bumbled into a materialistic society
When used in your sentence, that should give the impression of a lot of seemingly undirected movement resulting in the transition you describe.
In both cases, the phrases would indicate that society did what you ascribe to them without consciously deciding to do so; that it was asleep at the wheel, so to speak. Slump implies an almost callous disinterest as a causal connotation, while bumble implies ineptitude.
You might also choose blunder, stumble or fumble as fine synonyms for bumble in this case.
For slump, you could also consider slouch, as in the title of the book "slouching towards Bethlehem", a collection of essays which together depict the sort of "arrival due to aimless wandering" I think you're looking for.