Sure, the logistics of a change-over are many and can get complex. Added-on units are a decent solution, and for those that never wanted pets on their property, if you just grant a bit of space for dog-walking, that's all I need. We typically seek out the larger parks during the day anyway, so we wouldn't need access to the entire property. I'll pay for the privilege of bringing my dog and I would expect that fee to go towards the upkeep of the units added on. Sell those units to people with dogs, or those that are ok with having pets in the units.
Market share is growing, sorry I have no ready stats to base that on. More of us have pets instead of kids, so the pets are our kids (bash me all you want, I have a furkid). I see stuff all the time in our local paper about how "pet spending" is going thru the roof. It's there in the mainstream, if not the hardcore ts folks.
Silverleaf is onto something. Plenty of activities for the kids, big resort for walking the dog, a VERY REASONABLE fee for being able to bring the dog, and all the units I've stayed in have at least nice, if not VERY PLUSH. I've stayed with them 3 times in the last year. Their mf are high, but it's not because of the dogs, it's the wide variety of activities and amenities.
If you take a poll, you have to cast a broad enuf net over a large enuf base throughout the various regions. Don't forget to stretch that net to Indy - we just got our 4th Bark Park and have plenty of doggie bakeries and other dog-friendly areas and have plenty of doggie sports. No timeshares, tho, since we aren't exactly a hotbed for tourism.