Consider a $75k salary in Texas. That's $4766/month net (or thereabout), due to lack of state income tax. Let's say you pay $1k/month in rent (very realistic for most of Texas). That leaves you with $3766. That $2750/month figure won't be too far off if you don't have any dependents and live frugally, especially if you take advantage of tax-advantaged savings (like a 401(k)).

The thing is, you can make more than $75k in Texas, especially once you've got a few years of experience under your belt. So while I completely agree that it's not going to be attainable for everybody, I think it's not so far off as many might think.