I disagree that a BCT cannot support a comapny strength LRSU, but will say that LRSD would be a great start.
LRS brings a lot more than ground ISR capability, they can bring a SOF like capability to the BCT cdr, as well as being a force multiplier, especially due to the insertion and advanced skillset capabilities.
Imagine a BCT that can deploy LRS teams ahead of ground operations, giving ground ISR as well as CAS/Fires support, coupled with a abilities to perform surgical DA with follow on SSE. Just the PR capabilities at the BCT level would be a major improvement.
Now imagine if you could tie in a SIGINT capability and UAV IAR's at the BCT level, holy shit.
That would change what and how a BCT could affect the battle space on so many levels it would be unreal. Of course you would have to have competent commanders at the BCT level and you would inevitably piss off a bunch of other command levels laying claim to all those capabilities, etc.
Pipe dream, I know, but it could work and it would make the overall BCT capable of truly independent operations.