Gene, define "program material" as there quite a few films that go much lower than 20hz.
It does not matter if they do.
What matters is good performance to 25 Hz or so. If you can get -3 db at 20 Hz in room that is more than adequate.
What really matters is being able to do acieve effective spl, and integrated with the rest of the system.
Remember there is no such thing as fast bass.
When you have deep bass with a snap to it, then there is a huge upper bass, mid and HF component.
Listen to any reproduction below 80 Hz with a fourth order low pass filter, and all you will hear is a rumbling sound. There is nothing fast about it.
Having said that I like a a bass that is not over resonant with a Qts of around 0.5. However if I play any selection with the low pass at 60 Hz, it is still just a rumble. It takes the rest of the system to make it sound tight and realistic with huge slam.
I don't even use a sub as such, but the system has good spl and any explosions shake the floor and threaten to push out windows if you are not careful. Design is -3 db at 27 Hz, but in room measured, because of room gain is -3 db at 20 Hz.
It would not make a wit of difference if the F3 point were lower, no matter what was recorded on the source.
Another thing I have noticed is that efficient bass systems seem to sound better than brute force inefficient ones.
The old adage: - "Do speakers have to be large? No, but it really, really helps." I think that will always be true.
The bottom line is this, and its counter intuitive, but correct. Realistic bass that gives that sense of being there, is far more dependent on the main speakers than the sub.
Your main speaker system is always the place to put your money.
A a really good speaker system with a sub with an F3 in the 25 to 30 Hz range, will have much better and more realistic bass than a poor speaker system with a sub that has an F3 below 20 Hz.