As DM i handle ammunition very loosely, assuming characters recuperate fired ones whenever possible and once in a while may buy some more to reimplish inventory.

Quote from 6thLyranGuard >>

That comes down to spell selection.

 
True, but c’mon now. I could just as easily say “it comes down to weapon selection” since greatswords don’t use ammo. We’re talkin’ big picture, overall, spellcasters as a whole demographic as compared to martials overall as whole demographic, not individual case by case spellcasters here.

Quote from IamSposta >>

Quote from 6thLyranGuard >>

That comes down to spell selection.

 
True, but c’mon now. I could just as easily say “it comes down to weapon selection” since greatswords don’t use ammo. We’re talkin’ big picture, overall, spellcasters as a whole demographic as compared to martials overall as whole demographic, not individual case by case spellcasters here.

 Sure, but the difference is that a bow is something most martials who are built for ranged fighting will be using every fight, while spells with expensive components are usually high enough level that at most you're casting them once per day.  It's a bit of a different situation.

Quote from 6thLyranGuard >>

Quote from IamSposta >>

Quote from 6thLyranGuard >>

That comes down to spell selection.

 
True, but c’mon now. I could just as easily say “it comes down to weapon selection” since greatswords don’t use ammo. We’re talkin’ big picture, overall, spellcasters as a whole demographic as compared to martials overall as whole demographic, not individual case by case spellcasters here.

 Sure, but the difference is that a bow is something most martials who are built for ranged fighting will be using every fight, while spells with expensive components are usually high enough level that at most you're casting them once per day.  It's a bit of a different situation.

 
Find familiar is certainly not high level. Now, the components might not be expensive, but if you swap out your familiar’s form a couple of times, or it dies in a fight, then you’re casting it 2-3 times per day, maybe more. You know plenty of people do that. That’s 10gp worth of M components at a pop. If you don’t make ‘em track that stuff, the spell ends up getting abused by some players, and tracking that stuff, and other oft forgotten components is what balances things with martials.

There is an easy out for any martial that doesn’t want to track arrows or even carry the weight of the bow, quiver and enough arrows to last a while - magic initiate (warlock) then take Eldritch blast as one cantrip. Unlike most cantrips that do added damage with the single attack EB does additional attacks at additional foes ( or the same foe) duplicating the archer’s extra attacks but doing (potentially) more damage (D10 vs D8). 

Convincing an Artificer to put a Repeating Shot infusion on a ranged weapon of your choice would probably be easier.  And wouldn't require you to make attack rolls with what's likely to be a low stat for a martial unless they're a paladin.

Or give the martial decent charisma to use.

Quote from Wi1dBi11 >>

There is an easy out for any martial that doesn’t want to track arrows or even carry the weight of the bow, quiver and enough arrows to last a while - magic initiate (warlock) then take Eldritch blast as one cantrip.

That is by no means an "easy out" for a rogue, a Battle Master fighter etc., whose main features require weapon attacks

Anton, notice the 9 words after easy out please - I limited it to archers or the archery aspect of other fighters.

Quote from Wi1dBi11 >>

Or give the martial decent charisma to use.

 If they're not a paladin, they probably have other stats that are more important to their build.  When you're advocating bumping up a tertiary stat to support a feat that doesn't give a stat boost, it's not a simple or easy solution.

Quote from Wi1dBi11 >>

Anton, notice the 9 words after easy out please - I limited it to archers or the archery aspect of other fighters.

Yeah, those nine words aren't the qualifier you think they are. I mean, I'm playing a Battle Master crossbow specialist right now. I should know

Or how would any fighter get use out of the Archery fighting style with a cantrip, to offer yet another example of why eldritch blast is not a 1-for-1 substitution for a bow?

Mundane ammo, I'll tend to assume is just restocked as and when they party are around a settlement - non mundane or magical ammo that gets tracked like anything else.

Personally, I think Ammo serves the same purpose as spell slots really. It's designed to reign in and force changes in tactics and strategy when resources run low, thus changing up play style. I tend to like this and do perfer a management of resources if the rest of the table are up for that.

6th, Anton, no it’s not a perfect fix. On the other hand the great weapon and archery feats and styles look to be getting a bit nerfed given the UAs. Battlemaster archer would not be a good choice I’ll grant but there are plenty of subclasses where a higher charisma would be useful. Where it does work well are rogues and rangers who don’t get the 3rd and 4th attacks that fighters do.  
martin, yes, tracking ammo, rations, encumbrance are all ways built into the game to force balances, limit runaway fantasies and require tactical thought by players.

Quote from Wi1dBi11 >>

Where it does work well are rogues and rangers who don’t get the 3rd and 4th attacks that fighters do. 

No, it doesn't work for 99 percent of rogues either, as they can't use Sneak Attack on an eldritch blast. Swapping 6d6 damage at 11th level (when fighters get their third attack) for 2d10 is not generally something most people are going to be interested in doing