I don't think this is anything new, nor LLMs are to blame here. Although - LLMs want to make you happy, or maybe they don't think about what user actually needs, just how to accomplish the goal that was stated; they do stuff without asking questions (unless you constrain them or plan first). I've actively put in a hook for my agent to not make decisions on their own and ask me when it detects it's about to make a decision.
I think where a lot of people run into problems with the KISS principle is they conflate simple and easy. More often than not, simple is hard. Which is maybe a soft reason why agentic coding, which is all about trying to make every task easy, leads so consistently to complexity and bloat.
If you write your prompt as a request, and not carefully as an idea or suggestion, the bot can blindly agree to 'help'. And if you are stubborn about it, you can lose hours on something that cannot work, or make the code infinitely worse.
However, it's also the path of getting better at programming. To learn to take a step back, to ask yourself if it's really sensible. Just that now it also involves questioning the bot's help, as well as writing your prompts to prevent it.