Mages are inferior to melee

Could someone please explain to me what the point is of playing a mage when and so on all exist?

I've been a Morgana main since S3, and I've never seen the balance this bad. It's bad to the point that I'm thinking about quitting this game.

Melee champions can kill mages in two seconds (as measured by death recaps). If a melee can touch a mage, the mage is probably going to die.

Even when the melee doesn't instantly delete the mage, the mage probably won't escape anyways, because of the below.

Melee has huge amounts of mobility. Teleports, dashes, ect. The large amount of mobility skills that have been piled on melees has trivialized the advantage mages are supposed to have, i.e. being able to attack from a distance. It's very difficult for a mage to position in a way that stays in spell range but also stays far enough away from the melee champion because the melee champion can often chain multiple mobility skills, and the mage has no escape options except to burn flash.

Even if the mage finds a way to win this one-sided positioning match, many mage spells are skill shots. Since these abilities have to be cast from a distance for the mage to avoid just being gasp close + deleted by the melee, the high mobility melee champions can easily just dodge tall the mage skill shots if they pay attention. This is especially true for mages like Morgana and Lux whose skill shots can't pass through minions.

Even if the mage lands a spell, it's far from the imminent death scenario that occurs when a melee champion hits a mage. Mage spells simply don't do enough damage to matter in many situations. To use Morgana as an example, I've seen Yasuo players not bother using their wind wall and just absorbing skill shots because they know the damage is too small to be worth dodging.

TDLR: Melee has burst damage, higher health, and tremendous amounts of mobility. This combination has trivialized mages, whose traditional advantages of CC and casting from range don't matter in the face of the excessive mobility and burst of the melee champions. Low mobility mages need some help to be relevant.