@Cdmuz, sorry to hear of struggles securing a housesitter.
We’d recommend that you add your THS listing to your THS Forum profile. How to add a listing or profile link to your Forum profile!
THS does not publish data on number of pet parents or housesitters, or frankly much else for that matter. That said, there seems an increasing trickle of THS Forum threads in regards challenges in securing a housesitter. Suggest that you use search function to peruse related threads. Underlying issues were not always lack of housesitters - sometimes challenges may be have been (at least partly) due to poor listing information/photos (text, photos, completeness, insight); unreasonable expectations (pet responsibilities, dates); undesirable pets (many, behaviour, sleeping, separation); location.
If you add your THS listing to your THS Forum profile then perhaps some enthusiastic THS Forum members may be able to provide feedback and help you to secure a great housesitter.