I can speak to another resort where this happened:
Tropical Breeze Resort, in Panama City Beack was destroyed by Hurricane Opal (October 1995). The HOA did have insurance, but the HOA was still controlled by the developer, and he managed to take off with the money, and used it for other purposes. Even so, there is a positive ending to the story.
With no money available to rebuild, a group of owners set out to make things right, and took over the HOA (and filed suit against the developer and the old HOA board members).
The HOA tried to find financing to rebuild, but the HOA only owns the inventory of units turned back to it, if they choose to accept them (in our case, the HOA at one time ended up owning about 40% of the inventory). Financing almost came through a few times, but eventually, we decided to go ahead without. The HOA instituted a special assessment of about $3000 per unit week, in order to start rebuilding. Deed-backs were accepted for those unable to pay, which is why the HOA ended up with 40%. A number of units were eliminated in the plans for the new resort (the few remaining owners of those units were reassigned units from HOA inventory through an update to the Condo Association Docs on file with the county).
The HOA didn't collect enough to complete the project, and rather than ask for more from the owners, decided to sell the HOA inventory to a different developer, with provisions in the bylaws to prevent that developer from ever gaining control of the HOA. In exchange the developer (Coopershare, which is now Escapes! Resorts) agree to complete contruction. Fast forward a few more years, and the resort opened - and has been for I think 3 years now. "Original" inventory was sold as deeded weeks, but the Escapes! inventory is now sold as part of their internal points program, which exchanges through II. This has caused a few bumps along the road, but has worked out well. Most of the owners that remained involved use their week, leaving a smaller number of people exchanging through RCI, and our 1BR week trades quite well. We purchased resale after Opal, but before the rebuild back when TRI West had a Christmas Auction, for $500 and paid the $3000 assessment, so consider our real cost of ownership to be $3500 (plus closing costs). We were able to pick up a second week on eBay last Christmas for $1 plus closing costs, there were no other bidders, but someone not familiar with the resort would have had some issues, as the deed was one of the ones that was reassigned.
So to answer the original question, yes a resort could be rebuilt, but it may take significant time (10+ years in our case), if there is no insurance money. The insurance is the responsibility of the HOA, and is taken out on the property as a whole, not on individual ownerships. While is may not be clear what the fair market value is of a timeshare unit, both the FMV and the cost to rebuild for the entire building should be relatively easy to determine.