In 5e you could increase Soak to no mechanical benefit as after a certain point you could buy enough hits to shake off any damage from a gun. In 6e you can increase DR to no mechanical benefit as after a certain point you've exceeded any Attack Rating you're likely to see.
As a GM I didn't like the huge variance in PC defense and soak pools that you found at 5E tables. But, IMO, 6E was an over correction as significant investments in DR don't pay "enough" to be worth it. Dermal Armor, Ortho Skin, Mystic Armor, all really expensive choices for what you gain.
Hopefully future 6E supplements will give some Quality or Edge Actions or something for the high end DR builds. Something that triggers at +6/+8/+10 or whatever.
Shrug it off! 3 Edge, if your DR is 8 or more higher than an incoming attack that attack does no Damage.
Quality You got nuthin! If your DR is 6 or more higher than an incoming attack gain +4 Dice on a Charisma + Intimidate check.
ect, ect, ect. Lots of ways to use the mechanic to make a higher DR mechanically desirable if they wanted to.
(Keep in mind I don't have the 6e book yet)
I think part of the reason is also thematic.
I admit I don't know the rules for 6e, so I will not talk about them beyond from what I am understanding.
In the previous editions, it is true you CAN get stupid amounts of armor. No denying that. BUT, that doesn't mean you could actually do that 100% of the time. (hence the reason for the wide range of armors and options).
I am sorry to tell you this... but you just can NOT wear your heavy Mil Spec armor to a dinner party

But you could wear an armored up Tuxedo, or dinner gown...
Naturally, your gown or Tuxedo wouldn't be as effective as your Mil Spec.. but at least you got in the front door.
Situation and circumstance usually dictate armor values in the
actual game, far beyond shopping wish lists. (although the wish list comparison works for showing the "wonky" sit of things). And if you were allowing your troll to go to Dinner parties in mil spec armor, and were complaining about armor values in 5e....I don't don't think you'll like what I have to say
And, if you can't count on 3cm of ceramic hardened ballistic fibers to stop lead dead in its tracks, you plan around it. Or maybe you modded your armor for synergy with your team. There was options...
Even against the most heavily armored troll, you still had options.... Stick and shock ammo for stun damage (because while trolls do have huge health pools, their stun pools are usually tiny). Or gas grenades... or spells.
Now, from the sounds of it (and ONLY from the sounds of it. Again, I don't have the book, so just relying on what I understand 3rd hand), This aspect of the game has been reduced (or maybe just redefined??)... Which does concern me at bit....(although i have no doubt that the usual range and styles of armor are still there, along with the huge pile of mods).
It just sounding a little too... subjective... (basing this off other posts I have read).... What counts as an "advantage" seems to boil down to a simple judgement call instead of a mechanical advantage that has been defined...
"Alright, Timmy gets the Advantage, and thus the Edge to spend. Why? Well, his gun is Pink.. and distracting you by how awful it looks. Yes I know you have a laser sight, and smart link, but so does Timmy, hence the pink gun wins!"..
I really got to get off my ass and buy the book and read it...