Sorry, but the fins are not flexible. The trailing edge is, but the leading edge has a stainless steel rod in that can be bent if something is hit.
As for going ashore, you can remove the Mirage Drives as you stated, but it's easier to simply put one pedal forward. When you do that, the fins fold up next to the hull (it can be locked there as well).
Yes, you can go farther and faster. And, if you prefer paddling, then paddle!
Sorry Eric, but the Hobies have many advantages over traditional kayaks, many that have already been mentioned.
However, what may be the most important advantage not mentioned yet, is that women love them as they're so easy! That's a big plus in my book. It has to be fun for them as well!
And Eric, I'll also put it another way as you say, the funner a kayak is, the more it will get used. You need to try one before you say a normal paddle one is far superior. You just may like it.
And, as mentioned already, the only disadvantage is the price and weight.