It's not good info. Way too full of "what ifs" and no quantitative evaluation criteria.
If you have driven a long distance with almost no coolant over flowing ...
Under what circumstances? How much is "almost no"?
The overflow tank has "Hot" and "cold" levels marked on it. That is your guide.
If some of the coolant that
might flow to the overflow reservoir is leaking out, that amount is skewing the amount perceived as going into the reservoir. If there is a leak, it will not go away by replacing the radiator cap.
There are plenty of instances to complain about where parts (seem to) fail prematurely, but these vehicles are designed, mostly, by college-degreed engineers (and cooling systems aren't leading-edge technology). If there is a leak, it's either a poor design or poor manufacturing. Probably not a poor design or there would be mass horror stories about them, followed by a design change.
When manufacturing a million (?) of the same part, some are going to be bad. Did You get one? Maybe, but it's seven years old, so maybe not.
My suggestion is to replace (or repair) the radiator, thermostat and cap, get a good flush, and move on.