This is true, online games have always been full of aimbotters and cheaters.
If they seemed less plentiful it's because of the Admin:Player ratios. Back in the day, the game company didn't host the servers they just provided you with a server executable and instructions. So any servers that you played on were paid for by a person or group and that person or group usually moderated them pretty actively.
It wouldn't be unusual to play on a server where 2/3rds of the players had the ability to kickban cheaters. Now, you're lucky if a human admin ever sees a single match that you've played.