Not really, with a little discipline it can work for the vast majority of scenarios. 90% of my flights are backpack only and that includes travel where I needed to be dressed formally and travel with my SO. The only scenarios where it's actually necessary I see is if you need health equipment (which most people don't), if you have toddlers (which I'd argue you shouldn't be flying with anyways), and if you are moving a lot of stuff (where paying for luggage is still cheaper than shipping in many cases).
It just requires a little planning which I think most people my generation and younger are getting used to.
But this whole thread is about dark patterns, and this is just an example of another one.
And to be honest, the only way to not pay for your luggage is if you fly VERY light which is only applicable for certain flight scenarios.