As said above, fewer than in the past, before Offshore's proliferation and many middlers lack for need to be in LV or the middling market's demise from past glory, but still an healthy quota of the elite live there.
Being there helps the elite play into a multitude of banks that are guaranteed(sans a Sport Of Kings,etc..), allow them to move anonymously via runners(their own or mover's armies), allow them easy square-up and collection via movers(which may also be used to fire into NYC, Offshore, & all points in-between), handle beards, runners, & informant affairs up close(ex: payments, collections, daily pocket shakedowns, & balance sheet work), keep accounts fresh stocked and renewed,etc..
The creme de la creme sportsbettors have friendships and connections to sharp info and endless smart marks, so they can earn even outside of areas of expertise year 'round, even when they no longer work daily cards very hard anymore or at all..especially pros that aren't card players or can't afford to play golf or do lunch daily due to the demands of pro sports capping.
The nation's sportsbetting elite were playing LV, NYC, The Seaboard, the Midwest, LA, SF, and towns you'd never think had giant or connected stateside stores, before the first credit shops offshore appeared.
There are about 20 to 50 plus that primarily drive the movement(most are in LV), their orders & unit size can vary greatly(and most BMs know how to guage their plays in relation to linemaking), some are originators in shaping the number(irregardless of the amount dollars played), some are just followers(and can be jerked off greatly for number-building purposes), but even some of the followers' market-savvy, info, and dollar volume still must be respected much of the time.
Just as NYC and Chicago are financial market hubs(stock and gambling), Houston the energy capitol, LV despite Offshore's growth will always remain sportsbetting's intellectual mecca.
Fish, chances are many of the times that you ate at Andre's, Tillerman, Celebrity Deli, Cafe Michelle, Port Of Tack, Pieros, Ruth Chris, Mortons, Yolies,etc..you were in the company of quite a few of this bunch, if only knowing their legwork people by face.
Journey, it's not necessary, but it is still the best place to be if you are gonna make a fulltime go of it, especially if not sitting with the info in an offshore or stateside place of strategical importance..young man go west!