Journey On has been launched on every type of paved ramp, from Spanish, Ontario, Canada to Long Beach, Ca. (to quote the worst.) We've never needed 4-wheel drive. Just be careful and slow pulling the boat out. Since I'm cranking the winch, Judy is driving and yanks her out and hasn't missed yet. With an automatic transmission, you can slowly apply power, and get it started without wheel slip. In fact, the latest truck doesn't have a locking differential, but never a problem getting her out.
Fortunately, we can launch Journey On without getting the rear wheels wet. In Spanish, the ramp was broken, and I had a 4-wheel ready just in case, but it came out easily. In Long Beach, there was sand on the ramp, but still easily came out. Haven't met a bad ramp in Washington from Bellingham to the Columbia River.
4-wheel drive is expensive and you have to haul it around when you're not using it. I've been going to the desert for 50 years, and never felt the need for it. Looks good though.
If you have it great, use it. I've seen guys smoke all 4 wheels on the ramp. Spectacular. And I've seen guys get stuck in the desert with 4-wheel drive.
Boris