From my foxhole based on military experience and [civilian] logistics, I have seen this:
o High consequence and very likely to be scrutinized after the fact things like issued duty ammo, once "approved" and fielded by a significant "player" will be mirrored by MANY
o It is not a must field "NOW" thing, so the approval/purchasing "Agents" will put the manufacturers / developers thru the ringer with seemingly endless testing and evaluation. The time and money this takes cannot be understated (i.e. The US Army taking 5 years+ to change from the M9 to the M17)
o Once approved and fielded head offices will be very hesitant to deviate from it. Different "Agencies/Companies" not willing or wanting to go thru the fielding/testing pain themselves will just call for the known and approved thing.
o Additionally, they quickly committed to contracts and processes locked into the approved thing (No substitutions)
o In short order, other things with multiple variables will spec this now approved thing (Again, to reduce variables) i.e. all Army testing for the new 9mm was done with the same NATO 9mm ball.... Change up the ammo and end results become possibly unknown
o Example: the HST is 100% vetted and fielded, it is a known low risk component. No way of knowing for sure, but if say the Punch ammo is 95% as effective and 99% as reliable for 20% less, the head office simply will not deviate from the known/proven.... The head office is just not willing to invest the time and $ to find out IOT save [x], they have bigger fish to fry; it's not broke and no point trying to fix it
FWIW: 9mm & .357; I have a small qty of HST I carry; I have been backfilling with Punch and Sig carry ammo to save ~20%. In a year or two It will be gone and I'll probably stick with just Punch/Sig SD. .45acp: I have a lifetime supply of Speer Gold-Dot, honestly I wish I had the $ and a 20/80 % mix of "Spec" -vs- "Probably just as good" (Maybe some day I figure out a way to trade it, more likely my kids will sell it off at a penny a round when I'm gone LOL)
The Sig VCrowns in 9mm went though a minor design change about 2-3 years ago. They are pretty good. Loaded a little hotter than some +p which helps - they used to fail in cloth occasionally, not as much anymore. Mine are all 2 years old, and I've yet to have one not expand when I've wrapped old jeans around water or pork. I'd buy more if they were cheaper than HST for me.
I weighed some VCrowns and some HSTs a few night ago just for funsies. Both 124 - and the VCrowns are all heavier by about 2-3/10 of a gram. Could be the case or bullet, but I think its powder. I've got to save a couple of spent casings from each and compare next.
If I had a lifetime supply of Gold Dots I'd be in high cotton. I probably honestly have a lifetime supply of carry ammo if I'd just quit shooting it all up and go back to changing it out a couple of times a year - but it's just so fun to bust out of date cans of beans and soup and the like.
I've also got plenty of JHP's that don't really expand and a bunch of ones that expand well enough to do the job but aren't as pretty as the high dollar stuff............ but that's for the upcoming zombie apocalypse.