The reality is we're going to have less assets and resources available in the future. The threat environment is also going to be higher. Given that, the question becomes what's the best way to reasonably achieve our goal? You may indeed be able to have two UH-60s for each V-280, but that's just one component. What gets the mission done and what it costs to do so is really the question. Once in production we could probably turn out H-19s real cheap. Of course we'd have to have a lot more of them, the maintenance would be horrendous and we'd have to have lots more places for them to operate form. Similarly, We could buy a slug of P-51s or F-86s for the price of an F-15, but would that be a smart move?
Given today's threat and fiscal environment (we're going to have fewer aircraft and bases even if we built H-60s forever), the cruise and range desires for FLRAA make sense to me.