I don't think you pay as much attention to lore as you think you do. Oliver got the 'Wait and See' name from that being his usual strategy. The Fiends are right on their door step, and their resolve is 'lets send mercs to do the work'.
Money is the one thing that the NCR has, makes sense to essentially sub-contract the work to others.
They have resources to run covert ops into Baja, run a subterfuge food supply in Freeside, and all the crap they own, yet they can't send in a platoon of the 'big bad' Veteran Rangers?
How do we know that Baja is his call? If he's on the frontlines at the Mojave why would wasting resources of his own volition in Baja, which is apparently the consensus from the sage grunts of the NCR Army who call him "wait-and-see". As for the Rangers I'm not entirely sure how they interact with the Army, Ranger Milo claims to have no authority over even privates outside Nelson; from that I assumed that they operated basically as two seperate branches. The NCR Rangers joined the NCR Army of their own will right? They were once vigilante anti-slavers in Fallout 2. From Milo's comment I assumed the existance of some kind of "union" where both retain seperate heirarchies.
You can claim 'resources' all you want. But at the end of the day, Oliver is a bumbling and incompetent leader. Also, Cottonwood Cove, Searchlight, and Nelson are big loses. A Legion insertion point, a nuked base camp, and a Legion occupied butchered town. Right, 'acceptable' losses. To me, that's just bloody embarassing. If they can't even secure their own territory, they can't defend the dam. The ONLY reason they won the second Battle for Hoover Dam would be if The Courier aided them, House, or Independant. and two of those battles result in the winning the battle and losing the War in the Mojave.
Of course they can defend the Dam, the Legion is only sending operatives and scouts through the Cove; if anything relevant began happening their now the NCR have a Ranger outpost over-seeing everything (presumably established after Searchlight or that's just the Ranger's being incompetant). The Legion aren't - and don't - capable of attacking the Dam from both sides; all that's important are the number of bodies and bullets on the Dam, the NCR is entirely accepting of it's siutation really. The NCR isn't ready
defend Legion assault let alone attack the Legion, that's why they never attack the Legion's main base.
The way I see it is that Oliver at-least understands that preventing Caesar's assault is impossible and that it's going to be coming very soon - that much isn't contested by anyone. To that end his plan is hold the Dam at all costs; everything else could fall to pieces but on the day as long as the NCR keep the Legion on the other side of the Dam the Fumentarii as pissing in the wind. If troops need to be sacrificed from the Dam to retake a [censored] outpost like Nelson how does that help the battle of the Dam? It doesn't, it just means less people on the Dam to defend it and once the Legion win they'll pour through and take Nelson again.
Also, funnily enough, your whole line about 'Hsu chasing resources', that's what this whole NCR occupation is about. If you truly believe they're about 'spreading peace, love, and democracy' then you've joined the side of the sheep, pallie.
You know I hate the NCR. I see... when I meant
chasing resources I meant is that Hsu strikes me as the type unable to understand the concept of strategic losses, that sometimes men need to be sacrificed for the benefit of others; he strikes me as the type who would weaken the Dam by sending aid to Nelson, Forlorn Hope and anyone who asked - actions which I believe would be ultimately detrimental to the NCR because all that matters is the Dam.