The thing is, there's a narrative that these would be thriving communities full of families and children and it's just the mean nasty second homers that is stopping that. I spent a lot of time in Cornwall 20 years ago and it was incredibly deprived as well as inaccessible due to the lack of a motorway/ink roads, in fact, it was designated one of the poorest areas in the whole of Europe which is why it got so much money from the EU.
It's just not true that there are heaps of jobs in this area, and there also were declining school numbers prior to second homers. People with families often end up moving away for work, which is understandable. Most of the people living in social housing were never going to get mortgages and some of the estates on the hills were isolated, depressing and completely cut off financially and in other ways from the rest of the UK.
It was also, and remains to some extent, an area suspicious of outsiders and in those days that meant literally anyone who wasn't born there, I remember being stared at in the local pub! I still wouldn't be racing to live there due to this attitude.
I'm not sure Cornwall has it worse than anyone else, it's had the most amount of investment of the poorer regions and it hasn't lifted the economy off more than for tourism really, which is a shame, but then everyone did vote for Brexit having had this huge sum from the EU, quite incredible.