Not true... I live in Las Vegas since 2000. We don’t care and could live without the Raiders or imported franchise. The enthusiasm for the Raiders and the stadium from locals is not very positive, though the propaganda claims otherwise. The backers of the stadium and the franchise are blind to their overreach in expectation and support that the deal will ultimately produce. We don’t need the franchise or the stadium... and the tax and lease concessions are ridiculous that will stick the locals with a loss in the long-run. High-rise condos and/or additional convention space would be a better use for the stadium land.
Also, Vegas is not as pro-sports as you assume. Most of the traffic or fan-base will come from LA, Kalifornia or other die-hard football fly-ins... not from Vegas.
Though Vegas locals would be more enthusiastic in support of a home-grown football franchise... but at this time Vegas is an entertainment destination that caters to shows, boxing matches, conventions and gambling... not re-located/imported sports franchises.
This is not my personal opinion but is shared amongst many locals. But time will prove otherwise.
The new stadium will bring the super bowel, final four, nfl regular season games, stadium concerts, and a new stop on stadium-level circuits, such as monster trucks.
Currently, vegas offers everything else, but just not these stadium events.
So with the new stadium, Vegas (and Vevas Inc) becomes more complete as an experience-making destination. Which is good for the local economy.
As for vegas being pro-sports, the new nhl franchise Vegas Golden Knights has the third-highest attended games in the league. And they are a first-year expansion team. They are only behind ny and la, which are 10 times the size of Vegas. So the VGK alerady outdraw 28 other teams. Proof that Vegas is a pro-sports city.
And to address your concern that visitors will make up a good portion of the crowd at the new stadium, so what? Vegas is made for visitors. To return to the VGK example, at least a quarter of their crowds are tourists. Does a vegas local really want to disourage that? Vegas (which owes it's livelihood to tourism) is the only sports town (with the exception of Orlando and Anaheim) that should welcome sports tourism.