What is the point of an assassin?

ADCs hit harder, are more reliable, have higher range, have next to no downtime, don't have to ramp up their damage, have virtually no counterplay, have god tier sustain, do more damage, tankier than assassins...

Mages have higher range, do more damage, most have assloads of CC, most can just one shot you or global you, also don't have to ramp up their damage, also tankier...

Divers are more reliable, have better tools to survive when they fight someone, have CC, have just as much mobility, have very little if any counterplay, oftentimes do more damage, have better sustain, are tankier...

Juggernauts do more damage, are god tier tanks, have tons of sustain, have less counterplay and delay than assassins, and are capable of frontlining...

What does an assassin do? They have to either literally one shot someone, or they just die. They don't have the tools for longer fights, and they usually have pretty lengthy cooldowns on their method of killing someone and doing their job, they can't teamfight minus maybe picking one person off and dying (if they can even do that much), their damage is now delayed and heavily telegraphed outside of fringe cases... Half the time I feel useless playing one that isn't named Kha or Kayn, and AP assassins are just about synonymous with garbage at this point (unless your name is LB, but she's a mage) unless the enemy team somehow miraculously feeds you 4-5 kills early game.

I feel more like an assassin playing Yorick, Camille or even Lux, and that just isn't right.