In Texas, it would be a deal breaker. In BC, I don't know. We had two RVs in Michigan, neither had air conditioning, and we used them in the summer, one a travel trailer, one a pop-up camper. The twenty years I lived there, none of our houses had air conditioning either.
If you are thinking about taking the trailer to south Texas in the summer, no air conditioning would be a problem. Living in that climate now, I simply refuse to go "camping" at the time of year when the activity requires sitting in a plastic box with mechanical cooling. But you could have another RV use in mind, for which air conditioning makes more sense, e.g. motel substitute for traveling.