Given the amount of traffic that RNO would generate it doesn't make much sense for the airlines businesswise. There isn't a large population base in a reasonable distance to use capacity at LAX for a likely small ROI. Yes it's a pain to go through PHX and DFW but I don't see the business case for it at the moment. The population greater Reno area (if you go out as far as Winnemucca, Fallon, Truckee and greater Carson City) is less than half a million which doesn't make for a lot of traffic given the area's economic mix. A long time ago it might have made some sense, but given that the gaming industry isn't basically confined to Nevada anymore there isn't as much traffic coming in except during ski season.

In about the same distance radius from SMF you can get traffic from the Central Valley, the North and East Bay, the Western Sierras, and depending on traffic even central Silicon Valley and none of the hassles of SFO. There's probably more than 3-4 times the population base there and a lot more of them need to travel for work than Northern Nevada.