My FiL is housebound on IoW. It costs us around £60 for a day return out of season once a fortnight and around £90 in the summer. That's with a 20% Red Funnel discount. A longer stay in the summer can easily be around £150. You may find that's a barrier for visitors.
It's a nightmare. Fil has always lived on the IW, but his family ad friends have rather passed away or moved to the mainland. He needed medical care last week and it took 4 days to get the meds he needed from calling the GP to delivery from Boots. He relies on us to help from the mainland as he no longer has a support network, despite being in his house for nearly 50 years.
St Mary's and the council are struggling financially, especially as cuts are also being made in all their supporting services in Hampshire. Don't even think about trying to register with a dentist.
Some companies won't deliver to IoW, treating it like the Highlands & Islands in Scotland.
In the nice areas like Yarmouth and Seaview, second home owners turn up at Easter, but the community is dead for 6 months of the year. I think 4 primary schools are closing this summer, as locals can't get housing or jobs and rural schools are no longer viable.
The ferries, Red Funnel in particular, are unreliable. They suffer from a lack of investment and cancellations occur on a weekly basis.
Would I retire there? No way. It sounds lovely when you trot over for a short break and the sun is shining & you are fit & active Reality is very, very different, especially if you have no support from family & friends as you get old.