First, I don't see any issues with cantrips the way they are though I don't see any issue if folks want to look at other options.
However, the main reason I don't see any issue with them is probably because I don't agree with " but damage cantrips are just better than weapon attacks (even those made by martial characters) in pretty much every way."
1) Cantrips don't benefit from magical weapon bonuses to .. to hit and damage. You can get a wand of the war mage for the to hit side of things but most casters won't have an attunement slot for it.
2) Most cantrips do not add the casting stat to damage the way most weapon attacks typically do.
So consider ... a plain long bow attack at level 11 is 2x(d8+5) from any martial character since they all have extra attack by that point. Average damage is 19. Firebolt is 3d10 at this level which is 16.5 damage. Add a +2 magical weapon and the bow goes to 23 average damage. The bowman will also likely benefit from Archery fighting style significantly increasing the chances of actually hitting the target.
For sure, cantrips don’t put out as much DPR as most martial classes’ weapon attacks. The disparity will be different for different groups depending on how many magic weapons they tend to see. Still, I find the scaling in number of damage dice and the range wit no ammunition cost a bit much for my taste.
That is the lowest base ranged attack for most martial classes. It only scales up from there. A paladin with improved divine smite at 11 and the dueling fighting style with a 20 stat does far more. A rogue with sneak attack does far more. GWM/SS/Xbow Xpert/PAM builds can all do massively more damage than the piddly cantrips. Yes, the primary contribution of most casters is their spell casting but the spells are limited resources, none of the martial abilities mentioned here are in any way limited.
Divine Smite is very much limited, by spell slots no less. And sneak attack is very powerful but that’s to compensate for the rogue’s lack of Extra Attack. Still, I do see your point, and I was being a bit too hyperbolic calling damage cantrips “better than weapon attacks in almost every way.” I still think they’re stronger than they should be,
In my experience, when comparing cantrip damage to all the other options ... it just gives the caster something to do so that they feel like they are contributing to the fight and at least doing something when they don't burn a spell slot on a spell that may or may not be effective.
I get that, and I certainly agree that’s what Cantrips ought to be. For me though, damage dealing cantrips are a bit too strong. By all the means, give the casters something useful to do when they don’t have enough or just don’t want to spend spell slots. Just not something quite so good that it makes the archer feel like a chump spending arrows to do what the spellcaster can do for free.
The one exception to this is agonizing blast since, because it adds the casting stat to damage on each bolt, it remains competitive damage wise. Of course, SS/GWM builds will far outdamage it but it remains a useful amount of damage compared to any other cantrip damage options for most casters.
Ironically, Eldritch Blast with Agonizing Blast is in my opinion the most fair damage cantrip. Because the warlock dedicates a significant portion of their class features to keep up with the martials in terms of at-will DPR. An Eldritch Blast focused warlock is functionally a more magic-themed archer, and about on par with its martial counterpart, if slightly behind, which it makes up for with roughly one leveled spell per encounter. Whereas other casters, while a bit further behind on the at-will DPR get it in addition to a deep reserve of daily spellcasting power.
By level 17, when firebolt does 4d10 ... it still doesn't (and shouldn't) even keep up with the three weapon attacks from a level 11 fighter.
So, no, I don't think cantrips are just better than weapon attacks, because they aren't (with the possible exception of agonizing blast).
Yeah, that’s fair to say. I should have been more precise, most damage dealing cantrips aren’t just better than weapon attacks. I still think they’re a bit much, though. YMMV.