Hey wicked1,
I hear you and went thru exactly the same stuff you are, times have changed, go with it or sit home and cry in your beer. So here's what is happening at Big Bend N.P. Normally, 1/3 of the sites are first come first serve. But with Covid, they went to an entire reservation system, but did not add the first come, first serve sites into the system so 1/3 of the sites are unavailable and empty. Add the new demand that everyone wants to be outside due to Covid and you have limited opportunity. I just booked 13 nights in the National Park and 8 nights in Big Bend Ranch State Park, for mid January.
I spent multiple days and multiple times a day on the site and spoke to a customer rep a few times, but got it done. Christmas break and and spring break have always been the busy season there even without Covid. So I decided I would grab any reservation in January that I could. First, I got a week at Cottonwood, not my first choice but that was the only thing available, then 2 days latter I found 2 nites in the Chiso Basin and booked that, a couple of days later I was able to book 4 nites at two different drive-in backcountry sites, then a couple of days later I booked 8 days in BBRSP. It was very time consuming but I'm retired so I looked at it like my job and just did the grind.
People cancel all the time, in fact while I was on the phone, I refreshed the screen and a site became available for 7 nights the first week in January, but by then I had already gotten 13 nights and you are only allowed 14 nites. The customer rep told me that as soon as someone cancels, the system refreshes and the site is available, so it is worth checking multiple times a day. Once you log in a counter appears and you only have 15 minutes to complete your reservation.
So grab a coffee in the morning and get to work, then grab a beer in the afternoon and do it again. Don't forget if you have the geezer interagency pass, you don't pay the entrance fee and camping is half price.
I was extremely frustrated like you but now I'm a HAPPY CAMPER. Maybe I'll see you down there in January, I'll be the guy in the F150/Hawk combination with a big smile on my face and a beer in my hand.
Good Luck and be persistent.
2016 F150, FX4, XLT super cab
2019 FWC Hawk Shell
2009 Ford Ranger 4x4, XLT, Supercab total loss on 7/30/19
2014 FWC Shell total loss on 7/30/19
Towed behind our home which is a 2005 Kountry Star Diesel Pusher