If I was going to rent for any drive longer than 150 miles, I wouldn't own a car in the first place. Renting is a big hassle and multiplied by N trips sounds unpleasant. My trips are shorter and probably more frequent than your 620 mile multi-day affairs, though.

I guess my questions are:

What percentage of cars go on more than 2x 150 mile+ trips in a year? (Or 300 mile round trips that can be charged at turnaround point).

And the same question for 100/200 miles. I’m guessing 90%+ for personal cars.

And many of the exceptions are multicar households that could shift their long-drives to the other car.

To answer your question, I could only guess :-).

I don't know how common it is, but we're a single-car household that goes hiking (i.e., no charging at the turn around point).

FYI, the information for the US can probably be derived from the raw data available here: https://nhts.ornl.gov/ . The high level web summary buckets all trips of 31+ miles into a single bucket, which isn't helpful for your question, but if you want to do the analysis on the data, it's available. Cheers.