I'm no expert on the Texas system but for everywhere else, I have my Thanksgiving Rule which is that you can't complain about a lack of interviews until after Thanksgiving. That's why it is called Black Friday. 😉
Seriously, it can take months to pour over thousands of applications and make a few hundred interview invites. When the invites will be for 3-4 months from now, you won't get them now because of the high likelihood that something will come up and some applicants will need to reschedule which is a time sink for admissions staffers. The best practice is to make the invitations not more than 4 weeks in advance of the date. So, even if you are queued for an interview, if there are hundreds ahead of you just by luck of the draw or the alphabet, you might not get an invite for months even though your likelihood of converting that interview into an offer is just as good as someone who gets one earlier.