Since I live in Texas, and have mutiple Rangers friends, I know a little about their team. So lets take them as an example.
Last year they weren't a very good team. Managed to get lucky and won a ton of one run games that could have gone either way. So mid season the owners didn't feel they could do a mass sell off and prepare for the future. The thing was they knew Houston was young and way better than them and will be for a few years. They don't have mega bucks to aquire mega stars, so the next couple of years they are just going to tank and rebuild and I can't blame them. There's no sense right now to get into an arms race you can't win with the Astros and Angels.