Blue_Ninja_150 is correct that there are a lot more motor choices when you get into reloadables, and this is one of the big reasons for utlizing them.
However, TwoWalks, you are correct as well - if you are using an RMS system for a flight, and the rocket goes bye-bye, whether it gets hung up so high in a tree that you can't get it, simply drifts away, or happens to land in the exact middle of a pond that happens to be inhabited by alligators (sorry, eugenefl...), then you have lost a considerable investment. You are also correct that one of the reasons for using reloadables is lower cost over time.
Sooooo..... you have to make your choices and then take your chances. Some people, who are independently wealthy, like Phil and Milo, intentionally sacrifice whole rockets and motor systems to the rocket gods on a regular basis. When Milo was still flying rockets, his approach to a launch was to keep flying a rocket with a bigger and bigger motor until he lost it. Phil is slightly different, he tends to go for the biggest motor on the first flight.
Some of us, who grew up in a different generation and are NOT independently wealthy, take an entirely different approach. I carefully evaluate the launch site, the weather (wind speed and direction primarily), and the rocket that I intend to fly. Then I limit the size of the motor for the particular rocket to give me a flight that I have a high degree of confidence that I will be able to successfully recover the rocket in the confines of the launch site.
Sometimes.... I might take somewhat more of a risk, but usually then I will employ single use (SU) motors so that if I lose the rocket I won't lose an expensive RMS casing.
Another reason for using reloadables is the satisfaction that some of us get from assembling the reload. I will never never never forget the first reload I launched. It was an Aerotech 24mm RMS. The reload was an F12. I used it in an Estes Broadsword. Previous to that the largest engine I had used was an Estes D12. When my son pushed the button on the F12.... the noise, the smoke... and the rocket went up and up.... and up and up... and up. We were dancing around and hooping and hollering like fools.
However.... the best overall solution as far as I am concerned is to find a VERY LARGE launch site. Then load the max motor for the rocket and let'er rip !!!!