how do casinos always win at roulette, is it even beatable?

Every time I see someone claim they've got a "system" for roulette, I get flashbacks to those dudes in the poker rooms who swear they always hit flush draws - never turns out that way. With roulette, the math always looks like it's stacked. Zero is sitting there waiting to ruin every even money bet, but people keep going after those because it's simple and feels safe. I've tried to find some edge, running numbers on series and progressions, but my calculator just keeps spitting out negatives long-term.

I'm curious if anyone has tracked sessions for months and actually found any cracks. I know in poker you can exploit bad players, but roulette is all machine and physics. I never get why people trust betting systems over just accepting it's a casino game built for them to profit.