They also have bigger fish to fry at the moment. If someone in Enclave Power Armor (the very best) comes to help them, they sure ass hell won't say no. I do agree some dialog (especially from veterans like Oliver or Hanlon, and Marcus should have had a big WTF moment) would have been nice, and the BOS should shoot you on sight for harboring it. Any Power Armor, really, should rile up the Brotherhood (save their own ofc), until you are chummy chummy with them. In terms of forbidden technology, this one is kinda number one.
Now, for my own contribution (didn't read all the thread, I apologize if I repeat something);
-New Vegas has been deserted for some time. Yet the Gun Runners can move into the place and start producing advanced weaponry without much trouble.
-Nevermind bombers surviving 300 years in a lake, apparently revolvers and lever action rifles are resilient to even more. Might explain why they have more kick than anything else in the game, including cutting-edge laser technology.
-On that subject, it appears moving to energy weapons was a largely useless move; good ol' guns still pack more punch (unless you factor in experimental technology, Alien blasters, and magnetic weaponry that should by all rights belong in Guns), are easier to find and maintain, probably easier to mass produce, don't give away your position in one shot, and in some cases have projectiles so painfully slow you would be lucky to hit an old man in a wheelchair a few dozen feet away, let alone a charging mutant killer insect of instant death.
-To make a flaming sword, put together a few motorcycle parts and a lawnmower blade, and grab an oven mitt. Aparently the fires are fueled by the sheer coolness of it.
-The Boomers can target you with their old artillery to a meter, fire instantly, and can spot you even if you are fully invisible to the naked eye and are skilled enough to steal a rifle from someone's back while looking at their faces without them noticing anything (let's not get into that). Those are some spotters and crew indeed.
-In Dead Money, all your important gear has too much radiation to pass the check at the entrance (said gear is also instantly teleported, apparently, and nobody saw a better use for this technology than confiscating slightly radiated items 200 years into the future), yet your pip-boy, who has been on your arm and on someone else's for who knows how long, does just fine.
-In addition, holograms are apparently capable of producing enough solid light to kill someone in two shots, while being themselves invulnerable to all damage. What's more, said technology is used to guard a casino in the middle of Buttfuck, Nowhere, while being developped at a top-secret research facility (presumably) owned by the government, who didnt bother using this undefeatable marvel in their own super-top-secret-really-important-don't-blow-it-up base, or recapturing it after the bombs fell.