And in any case both of those are less sensitive technologies - a transport plane that other countries sell equivalents to, and a previous-generation fighter plane for which India is in any case the largest expected purchaser (the production lines in the US are being wound down, and the move to India would be part of a purchase by the IAF), and to etch the US has already approved sales.
We wouldn't sell India a Minuteman, so we're sure as hell not going to find their development of an equivalent.
We came pretty close to that brink after not bothering to invest in our own engine development. Makes the quarterly reports look great though.
The US has not remotely lost the ability to launch people in the context you're suggesting (lost knowledge, lost budget, lost political will). Its literally between launch systems. No knowledge or budget has been lost. On top of it, its doing what no other nation seems able to do, spark a space race between corporations with their own goals and cost-cutting measures. That's on top of NASA's incredible record of space science missions and robotic missions in the interim.
As far as the RD-180 issue goes, ULA buys those engines and re-packages them into domestic launch vehicles that create domestic jobs and keep the majority of the profits local. There's a big difference both practically and politically between this and having a foreign company launch your satellites. So India is not being treated that differently here.
That said, RD-180 purchasing is being phased out. The Delta IV is being retired and that only leaves the Atlas V, which I believe is no longer allowed to buy new engines since an earlier sale this year. That's on top of the Pentagon approving $162m to help fund the AR1 and BE-4 engines which will ultimately replace the RD-180 for the ULA.
NASA has failed at how many launch system projects since the Space Shuttle?
(Assuming you learn from your failures)
There is also the issue of maintaining the capability domestically. If someone else is too cheap it would destroy the local capability. Imagine the US losing the ability to launch it's own satellites - like it lost the ability to launch people.
That said, there needs to be a way to make domestic launches competitive, so helping SpaceX or others while blocking foreign competition seem like a good idea all around. The goal should be to maintain domestic capability while hindering foreign nukes - not to maintain some company monopoly.