This is kind of a short history/issues that were dealt with.
1. Performance loss. With a kick up board, while it is down, you are left with a hole in the bottom of the boat that is the length/width/depth of the board. The faster you go, the more turbulence you create into the void. If you’ve been on small dinghys 420’s etc. there is a rubber seal that allows their centerboard to drop and keep the turbulent water out of the trunk at the same time. Allowing for a smooth underbody. Just wasnt possible to create something like that on a larger scale.
2. Can’t modify the boards for more performance. The trunk you build into the boat for the kick up boards limits any future modifications. With dagger boards? Make them as deep as you want, change the foil shape. All possible. With everyone pushing for taller rigs, larger sail plans, you outta be able to put the power down you below the waterline.
3. The GB60’s had hydraulic rams that controller the up/down of the boards connected with a “fuse” pin. Hit something at speed, pin blows, saves the board/ram. But replacing that pin is the fun part at sea. After all that, there would still be damage to the board.
4. If you need to pull the boards for repair, with daggers, attach a halyard and hoist. With kick up boards, requires a haul out to drop out from the bottom.