Frankly if you're wanting "free food" you get it by gambling at the tables in Vegas (casinos will happily write F/B comps if they see you as a customer that will drop thousands or more at the tables in theoretical gaming action). F/B is a major driver for hotel profits and Vegas has a lot of leisure travelers (as well as a fair amount of trade show attendees, admittedly) so the whole "executive lounge" thing isn't really a thing in that market and never really has been for quite some time. Caesars did have some lounges for high rollers but they got trimmed because Caesars status can be gamed and it's a way to do general cutbacks. There is a specific lounge you can get access to at Venetian but it's a lounge that's an add on to a room rate (or presumably if you can get the right comp), not one that's a status free for all.

Also, Vegas is just not a luxury hotel market in the same way NYC/London/Dubai/Hong Kong/Tokyo are. You have something like 10,000+ rooms in "five star luxury hotels", and in many cases the scale just doesn't work for handing out premium lounge access to everyone who has a particular credit card + Diamond status through stays. If you check out this thread you can see the Hyatt Globalists descending like locusts on a generous breakfast benefit that promptly gets scaled back. Something like that is pretty much guaranteed to happen for Vegas executive lounges were they "free".