Kevlar's not going to help tread life much. It'll help against flats, but not tread life. (I bought one of those wally world kevlar cruiser tires for the front wheel on my bike but haven;t installed it yet - I'm waiting for the original to get worn out...)
NOTE:
ANY tire should last longer than an hour. I got about a thousand miles out of the original tire on my bike. I would guess that you have your friction drive either misaligned, or not pressing down on the tire enough to get good friction between the roller and the tire.
The friction roller MUST be at 90 degrees to the tire, when viewed from the top (critical,) and from the rear (not so critical.) Any misalignment will reduce the tire life. And, the greater the misalignment, the greater the tire wear.
Now. As far as pressure. Your rear tire should be (if it's a standard cruiser tire) at about 50 psi. Then, lock the roller down when it deflects the rear tire enough to avoid slippage when driving. I put my weight into the frame when locking. Probably around 50 pounds of force. The trick is to have enough tire surface in contact with the roller to avoid just grinding the rubber away. For a starting point, I would go for a center of tire deflection of a quarter of an inch, or maybe a bit more. Make a point of noting the deflection each time, and the pressure, until you get a good feel for it. And, every time you change the tire, check it again a few times.
Finally. When driving and the tire gets wet - let up on the gas if you hear or feel the tire slipping. If you keep revving the motor, you'll wear a hole in the tire.
BTW - I just put an
Innova Swiftor 26x2.0 on my Staton friction drive cruiser, and I'm VERY happy with it so far. With the almost slick inverted tread, it's a MUCH smoother ride, as the roller vibration is completely gone. And the rolling friction is quite a bit less - I'm noticing between 1 & 2 MPH higher top end.