Could you reasonably merge a lot of the ones that have very few people in them???
Why would you?
They have a minimal government structure. Folks would have to travel further to the county seat when they did need services. One of the big services is is maintenance of county roads. Would the absorbing county provide the same level of maintenance. If there is a major crime, call in the Texas Rangers, and the trial will be in district court.
Exceptions might be Dallam and Hartley, and Potter and (northern) Randall.
Delegate maintenance of the county website to a regional council of governments.
I am talking about ones that have very few people in them. One of them has less than 100. Having fewer counties would make sense as a lot of the infrastructure is redundant.