I installed one of those in my last apartment. It cost $20, was digital, had a backlight for when I might want to manually override the program at night, and served as a handy wall clock too. No internet connection so no security hole. No privacy issues. Lowered my bill relative to its mercury-filled non-programmable predecessor. Paid for itself in like two months.
Nest was never a solution. The IoT generally is not, much in the way that the F35 is not a viable means of waging a large-scale war.
Maybe it wasn't a solution for you, but it is a solution for a lot of people. I too have had various programmable thermostats for years, and yes they were a great improvement over manual thermostats. You know what though? I don't have the same home/away schedule all the time. It fluctuates significantly. Sometimes I go into the office, sometimes I work from home all day. Sometimes I'm home in the evening or on the weekend and sometimes I'm not. So a thermostat which can automatically detect when I'm not home and lower the AC if I forget to do it on the way out the door solves one of my problems. And I've found other features of the Nest to be useful and it and has made a noticeable difference in my electricity usage.
So the Nest was a solution, just perhaps not for you.