From the photo, you can see that the bottom is not actually very thick. Maybe two layers of fiberglass/polyester resin with a thin coat of gelcoat on the outside.
I sail year around in Florida and usually have to do about two bottom jobs per year (either just adding more polyester resin and gelcoat or having to add some 1"wide fiberglass strips/resin and gelcoat) on my 84H16.
I trailer my boat and launch from a "rough sandy" Causeway where I can back the trailer down to the water's edge. Launching and reloading the trailer doesn't really cause much wear on the bottoms this way. Yes, I have a set of Cat Trax, but they are not easy to use solo and take a lot more time to use.
Most of the wear on my boat's bottoms comes from positioning my boat on the water's edge so I can point it into the wind. I don't pull the boat all the way out of the water, but just enough to keep it from sailing away on it's own due to power boat wakes, etc. I need to point the hulls into the wind in order to raise and lower sails and when stopping for a short break at an island, beach, etc. while the sails are still up.
The worst grinding on the gelcoat is when the wind is parallel to the shoreline and you need to pull the leeward hull up onto the sand and then rotate the boat into the wind and also when you re-launch it by having to rotate the boat at least 45° so you can sail off the shore.
Where the gelcoat wears off is a good indicator for where I need to do some repairs. I also use a rigid template to make sure I maintain proper shape.