Speaking as a former tomato picker, tomato greenhouses have to "rotate" varieties every two to three years as they lose their resistence to the various plant-type diseases, pests and fungus that are knocking about, no matter how well they are treated, and even then, the use and application of pesticides has been tightened up over the years anyway.
So, the only way to keep the different varieties coming in is to keep crossbreeding and crosspollinate plants and were named accordingly. When I first started in 1994, we were dealing with the "Superb" variety and went through various varieties over the years then ended up with "Pronto" by the time the firm I worked for ceased trading in 2011.
Each variety had their own little subtle differences, weak and strong points. As in leaves were smaller or bigger or softer or harder, the fruit were easier or harder to pick off, some grew faster or slower, some grew straight up, others has a habit of curling around, some produced more fruits per truss set, etc, etc.
The only harm it's done to me is that after the best part of two decades of handling the bloody fruit, I never ever want to touch, smell, touch or even look at another tomato again. I never even liked them before I took on the job, now I have a pathological hatred for them.