Monopoly over the economy? What economy? From the very beginning, House has made tourism the cornerstone of Vegas' economy, and for that he needs a clientele that's rich, comfortable, and looking for new entertainment. If you cut that foreign cashflow out, then not only does House see considerably less income, but most of the services dotting the Mojave (including the Kerrs' roadside grill at the 188, the Novac inn, and the Vikki and Vance Casino) would dry up from lack of customers (namely, tourists traveling to and from Vegas). All that would be left are a bunch of farmers, ranchers, and prospectors living hand-to-mouth, too poor to really be demanding the kind of luxuries House is supplying. If House wanted to cut off NCR and "monopolize" the Mojave's economy, then pretty much his entire model has to change and he would have to sell a completely different product than what he intends.
My point was...
House himself hardly seems to give the impression that his plan is to feed off of tourism forever; it seems like a way to jumpstart his economy. Something that he chose because it's what Vegas is capable of and because it would take money out of the NCR and into the Mojave, as tourism is perhaps the ONLY service the Mojave can provide that the NCR really can't.
Long-term however, House talks about wanting to get society back on track and back on the road to progress, talking about space travel and colonization on other planets. How is he going to do this with casinos alone? At some point he must change his business plan so that his people aren't just leeching off tourists, but producing technology and rocketships.
He then, again, states himself that after his victory at Hoover Dam, Vegas will see a dip in revenue for half a year at least.
My point is that to me, I start to question which decision is more profitable. Either he leeches off the NCR with casinos a bit longer or he starts changing his business plan around now. It's an inevitability if he's serious about his goals, and it seems as though cutting ties to the NCR would eventually become a profitable decision anyways, when they stop being of use (once their economy starts to tank) and they only offer competition. If not right now, wouldn't he perhaps support such a decision down the road?
House makes it clear that he doesn't like the Legion but if you ask him if you should kill Caesar he says something like "I don't want you to touch even a single hair on that mans head." He needs the Legion to attack the Dam. The sooner that happens the better for him. Nuking a Legion staging point would only delay House's plan.
The scenario I'm talking about refers to if we literally make the nuke decision DIRECTLY before taking Hoover Dam.
House doesn't want Caesar harmed because he needs Caesar to keep the NCR busy, not because he has any other use for them. Their citizens are probably the last who would ever consider turning to Vegas, as they've been taught very different morals, ones that go against the ideas of personal property, greed, drug usage etc. They offer no profit to him.
The NCR could, but my question was more about is the NCR's profit worth it in the long run? At some point in time, House seems to imply he intends to convert his business plan entirely, going from casinos to something else (probably technology production). If the NCR and the Legion both have irradiated borders, the citizens of the Mojave have little choice of where to go, meaning they basically HAVE to play ball with Mr. House. Money would also become a non-issue because if you look at the Mojave itself without outside nation involvement, House already owns a giant majority stake in the economy. The value of the bottlecap would change, but House would remain more or less unaffected by it.
Again, what use is there in leeching off another economy to gain money when you can directly manipulate the economy and the value of the bottlecap in your favor? The only loss I see is that House is of course more likely to find more technologically talented employees among the Mojave AND the NCR than he is in just the Mojave alone.