The idea the Dex is king is in comparison to STR for which to use as a melee character primary stat, Con need not apply unless you intend to defeat your opponents by living a long healthy life far away from them. A Str or Dex combatant very likely has Con as their secondary stat.
Dex affects initiative, and stealth, and thieves tools, which come up in pretty much every game.
And counting saves while ignoring spells is... misguided..
If you actually look into the SRD Spellbook, You will see that Reflex, Fortitude, and Will are still reigning champs.
12 use STR saves.
48 use DEX saves.
31 use CON,
34 use WIS,
2 use INT (although maze uses an INT CHECK, not save, so maybe 3)
12 use CHA
(Another 21 are attack rolls, which MIGHT be affected by dex, or even con or wis in for barbarians or monks)
Lets look at sample traps while we are at it...
Dex 4
Con 2
Also many magic traps trigger spells, which again usually targets Dex.
So yes, if you intend to run a game in which there is no magic and there are no traps, then by all means, Dex loses a lot of its impressiveness. But, if you do actually intend for those to exist, then at some point you are going to run into 8d6 worth of fireball.
Traps are by no means tied to Dexterity at all. In fact, most of them have attacks instead of saves. And yes, Dexterity affects AC, but so do Strength, as you need certain tresholds covered in order to use heavy armor: the highest basic AC comes, in fact, from strong characters (20 from shield and plate), vs 19 from dextrous characters. You could increase more than that with a feat (half plate and Medium Armor Master), but with an Armor feat you can also increase your durability giving your character DR 3 against BPS damage, which doesn't sound like a lot, but in fact it is when you factor multiple attacks (from one or multiple creatures). I have two characters with HAM feat in my table, and they are basically immortal against waves of enemies.
There are also a LOT of Constitution saves in traps (EG: anything including poison needles). And you can also trigger Strength traps, like falling debris or rolling rocks. And also, jumping is strength-controlled. I cannot count how many times the (10th level) rogue and elf wizard fell to simple pit traps having detected them, just because they couldn't jump over and failed their checks. The paladin and the fighter just jumped over them, not even needing a check (str 20 allows really long jumps).
Even with that covered, as opposite to monsters, the main effort is to avoid traps, not fall for them, so it's better to have a high Perception/Investigation (ruling) than high DEX for traps. That way, you avoid traps altogether. So, no, Dex isn't king over traps also.
That's different to say that Dexterity is useless. It isn't. Is very useful, specially for stealth and rogue's tools. But also Athletics, that govern anything physical (and has combat applications too, like Dexterity, that governs over Initiative).
As for the spells, I know that many are dex saves. I never denied it. Also I didn't count them, as spellcaster monsters are scarce and have extensive spell lists. I'll upload a list of spellcaster monsters when I reach home. And they also don't endure enough to use their spells. I do not lie to you: the last time I've seen a fireball in the hands of a DM was more than 5 years ago (playing AD&D). It is much more common to have spells from the player's side. Casting spells as a monster isn't often the best option, an when it is, it's usually a defensive/controlling spell (like Entangle or Shield). As I've said, this could vary a lot, but it isn't a joke that most of the Dex saves come from creatures above 10th level, when damage is more a nuisance to the players that a real threat. It is true that most monsters use Strength saves than Dex saves, and from them they are much more common (it is more common to use several lesser CR monsters in late levels than using one higher CR monsters at early levels). YMMV.
