lol - nothing negative or insulting.
I just disagree with your opinion.

And if you use a 3d printer properly, the parts can be stronger and lighter than injection moulded parts.
No it's not plug and play and as with most things the 'idiot' settings won't give you the best results.
So yeah you do have to learn how to use 3d printers properly to get the best out of them.
A lot of people just won't bother learning how to use it properly and will blame their machines for poor parts.
That's just the way of the world.
I'm not saying you're one of these - just that it's how things have always been.

And I doubt 3D technology will ever advance to the Same Durability level.
Well given that the automotive & aerospace industries are now making final use parts with 3d printers - you're out of date on that as well.
Plastic as well as metal parts.

And the quality gap between industrial plastic printers and 'home use' desktop printers is being narrowed all the time.

Disagreeing with someone is not a insult. Arguing with someone you think is wrong - is not being negative. If you think I'm wrong - back your opinions up with a good argument and if it's convincing I'll change my opinion - that's how argument works :-)