Mosaics on the outside

These are images of a beautiful mosaic being installed at the Children's museum, next to the Pen-Free Tampa Museum of Art. Hope the kiddies get more respect from museum management than their parents do! Anyway, I got to stop and chat for a few minutes with a woman who was helping the artist do the installation. She said they did the pieces at a warehouse, using Wonderboard as the backer for the mosaic. When I saw the panels, they were already mounted and I could see screwheads that were being covered up by glass pieces, as well as some damaged glass that they were having to remove and replace. Very magical. The link goes to an article, which gives the monetary costs ($75,000) and how payments would be made ($5000 down and $17,500 over a four year period.
I don't know a thing about public commissions of installation work, but this woman had a bunch of people working with her part-time and I'm wondering how this is economically feasible unless you have a boatload of these things going over a 12 month period, enough to float your materials, living/travel expenses, hired help and the inclusion of Murphy's Law costs. Anyone have any ideas about how this works?