Real-life experience (over several decades). For me, one hour of even intense exercise is good but not enough to get me to, and keep me at, a point near my personal peak athletic performance. YMMV.
Is this based on personal experience, or do you have a source?
My own science-based impression was that it's more important to break up sedentary time with activity, and reach higher than mild physical exertion at least a bit, than it is to target any specific amount of time.
To put it another way, comparing to 2hrs
Everyone has their own thresholds but paying double for 5-10% more doesn't seem worth it to me personally.