You are free to do you. But you were asking about why others want the best model.
The answer is, clearly, agentic coding (ie multiple agents each cranking through tasks independently) lets you ship A LOT more business value if used correctly.
And hey, don't get me wrong, you can get pretty far with just prompting. But the subtle misses and (I'm looking at you GPT) the overengineered 20k line PRs to do a simple thing are going to cost you a lot if you're not vigilant.
I don't think anyone is stopping you. This is an entirely valid way of working.
I for one am glad to leave that behind me. The sooner I never have to write another line of code the better (professional software engineer for nearly 30 years here, for context).