Modern close air support means dropping smart bombs from high altitude, to do this you need to be able to quickly get to the right place, the A-10 is too slow to be able to do this. One of the most effective bomb trucks is the B-1B.

I don't believe that's accurate. From everything I've ever read about the A-10 and close air support, the 'close' aspect means that you're close enough to get positive visual identification of friend and foe. Additionally, it means slower speed because the fast movers are too fast for this task. The third important factor that's commonly mentioned is length of time that the plane can loiter on station to assist the ground troops.

A B-1B (while being highly impressive in its own capabilities) is poorly suited for these things.

Actually the B1-B has done a huge amount of the sorties for CAS. It can respond quickly, has a huge weapons load, and combined with targeting pods, can just sit above a fight plinking targets. It's loiter time is much better than 90% of the fighters over Afghanistan.

The idea of getting down in the weeds (below 1K AGL) is not how CAS is done anymore. It's extremely rare to get that close. It's not how the A-10 is typically used.

Have we outlawed inclement weather? Or just leave the gomers to their own devices until the cloud cover clears?

Inclement weather would obstruct the vision of the A-10 pilots too. Today's CAS is largely a forward observer calling in a grid/GPS coordinate or lasing a target.

how are pentagon planners dealing w/ emerging tech hacking/jamming/spoofing GPS signals? I recall something along this sort being posted to HN a few days back, as well as this being perhaps the means of how Iran captured a US drone several years ago...

GPS is problematic in a contested environment due to low signal strength. Even with GPSIII satellites being deployed, it's susceptible to both jamming and spoofing, at a trivial cost. Normally when an opponent starts emitting (say with a search radar), you can target it with HARM etc. But the GPS jammers are pretty cheap, and don't require much power to cause issues.

This has led to dual/tri mode seekers on missiles. They use GPS until they reach an area where the mission planners feel GPS would be unreliable, then they fail over to IR, radar, or EO sensors for the final segment of the mission. If weather permits (and the threat is manageable), you can lase the target. Potential workarounds in the future are vision matching systems (kind of like the ALCMs tercom) that appear promising.

Against a peer opponent, jamming will be pervasive across all frequencies. Your comms might be secure in terms of compromise, but the sheer amount of multi-band noise will be something that (at least the US) many militaries will be unprepared for.

I hope the B-1B is cheaper in terms of total cost to operate than in the Reagan era...I seem to recall chatter that it was something of a hangar queen