The bigger issue, and I believe the primary reason for the rise in popularity of these bots, is when your performance does 'earn' you something. As the OP was speaking of TF2, this comes in the form of hats and custom weapons. Today's counterstrike game has weapon skins and knifes that go for pretty extreme real world dollars.
Almost every modern shooter has some sort of rank up system tied to rewards. Some of the worst examples would be PUBG's real world money trading of loot box items or Diablo 3's real world money auction house.
In my mind, these kind of systems turn video games meant for enjoyment into some weird NFT mining system where normal players are manually mining them with pen and paper while the bots have built ASIC devices.
In cases where the items themselves cannot be sold, you have people selling the whole accounts. There are entire middlemen businesses set up around this stuff. It's crazy but there is your primary driver for incentive.
I don't know about TF2, but for CSGO weapon skins & knives (and all drops) never come from gameplay wins. So there's no motivation at all to cheat for any monetary-related reason. Botting was a thing to farm for drops, but those literally just joined a server and spun in place to avoid being AFK kicked - that's it.
So CSGO cheating is purely about the human interaction components (eg, feeling good about winning, taking pleasure in making people angry, the thrill of getting away with it, etc...)
On the other hand, PUBG does have Battle Point rewards linked to performance. And there it is very common. Almost guaranteed to see a cheater every 10 matches or so. And there was an easy means to sell those rewards. Contrast that against Sea of Thieves. A game specifically about PvP and stealing loot from other players. I don't know that I have ever encountered a cheater there. But there is very little incentive to do so. There just isn't many vectors to turn virtual work into real world profit.
Seems to me that the lower the barrier of entry together with the higher the real world value of the rewards\drops gives you a clear scale of the cheat potential\incentive\effort. I think there will always be a small percentage of those doing it for the LULZ. You can combat that by raising the barrier to entry. F2P games seem to have a higher rate of these types.
When the reward system cultivates an environment ripe for abuse, it moves from occasionally annoying to game killing epidemic.
They can buy players /cheat to farm, then sell the virtual goods over to those with USD; with healthy discount as profit for the other end. Thereby transfering their asset out of China.