Well yes, I'm taking an extreme example.

I'm just thinking about something like the meteor missile, if you're up against a 5th gen jet with shorter range missiles, the 5th gen jet doesn't necessarily have the advantage.

Then there's things like drones. A cheap drone with a good missile is arguably the better option than an expensive jet with poor weapons.

Yes, the best option is the good jet with the good missile, but most militaries have limited budgets, so it isn't a question of having all the the things, but one of where that money is best spent. I suppose you could argue that the military knows best, but then the US military insisted on keeping cannon around on jets just in case, so it seems to me, at least plausible that the current view is more about inertia than bang for buck.