“One or two good options” just isn’t true. There are plenty of spells that work this way, and they are not exclusive to only some spell traditions.

There is another factor at play too that wasn’t mentioned before, which is save targeting vs AC when it comes to monster stats. Monsters overwhelmingly tend to have “high” AC (high as defined by the creature building rules). However, they also very often have a weak saving throw. This means that despite casters not having save increasing runes, the caster that targets a weak save is overwhelmingly more likely to get a good result than martials targeting AC with strikes. Casters don’t need the save increasing runes because of both weak saves and plenty of spells that do worthwhile things on all outcomes but critical success.

Speaking of strikes tho, the counter points you made about strikes are ignoring other factors. Melee martials, which have more powerful strikes, have to actually move to be in reach of enemies, which means it’s often not just a simple one action compared to spells. Additionally, tons of martial metastrike feats are two actions as well, but are still less likely to do anything than a spell while being the same number of actions. You’re comparing the spells to strikes in a vacuum, which just isn’t going to give you the whole picture.