On reason why this balance is so lop-sided is partially a natural result of higher powered creatures having higher statistics that they need to attack effectively, leading passively to higher saves as well, but that's more a cause, rather than a redress - the main value point that accounts for the odd balance here is that in all but a few niche cases, attack rolls are going to do one thing - damage - and they'll generally to it to one target, and little else. Conversely, the extreme vast majority of spells use saving throws, and they have broader effects; the value threshold of being able to do ~20 points of damage to five targets (presuming that half of them save) is generally going to be more in non-epic-boss situations than doing ~100 damage to 1 target. Unfortunately, in major boss encounters, a single target that needs to take damage is far more common, and it's the major encounters that people remember better; fireball looks great and flashy to use it on a powerful boss, but even if the boss is nor resistant, and even if it fails its save, and doesn't use a legendary resistance... the fighter is still almost definitely going to do more actual damage to the same single creature on their own turn. In terms of damage spells as well, you're always going to get some amount of pay-off, when targets pass your saves; all bar one or two spells that offer saving throws for damage, still deliver partial damage when the enemy succeeds - they'll succeed far more often than the fighter will miss, but you'll always be adding some damage at least, if you're using a spell slot to deal damage.
On the flip side, there's utility - the value point of paralysing four large threats until they can save out is huge, compared to dealing significant damage to one of them, or minor damage to several of them... and to a certain extent, in the high levels, if your control wizard could land that upcast hold monster as easily as the fighter can land a sword-stroke, then the age old complaint about casters being overpowered would actually be true (in 5e, it's very much not, and people who claim they are are holding onto the stigmas of past editions where it very much was true).
It's not a balance that feels good, a lot of the time - especially as someone who plays spellcasters more than other classes, I can absolutely say that it doesn't feel great knowing that in those higher levels, important enemies making their saves is the norm, rather than the exception. But, discounting cantrips, there are about 18 attack roll spells in our entire spell lexicon, from a list of close to 800 spells... do take a moment to digest that ^.^ (a lot of the spells with attack rolls are cantrips, though, and 1st or 2nd level spells, so if you're a caster who favours those particulars as your bread and butter, spell sniper may still be of value to you)
((The slightly less charitable part of me feels like adding that she feels that there were simply some folks on the design team in the early days who just didn't realise that it was as lop-sided as it came out, all factors together, and wouldn't be told before running it through for the JC stamp of approval... but it did get that stamp and go live, so the final decision was that it's not as off the mark as I feel it was. *shrugs* I'm not infallible, and not without my own biases.))
