Absolutely bonkers to say there are hardly any second homes as personal holiday homes. There are loads. 14,000 in Cornwall alone, and as many again are holiday lets (which are different, in that they are IIRC treated as a business, and they are occupied for much more of the year).
BTW re: lighting I mean that there are whole "dark" streets due to absent owners, no lights at windows, no lighting around doorways etc.
Although I sympathise somewhat with the frustration at those who sell to second-home owners, mainly these are people who either need to afford to buy elsewhere in the similarly priced local community, or move into sheltered housing and pay for their care.
TBH the banks are to blame somewhat for funding the ridiculous house price explosion. Twenty years ago in my local area a terraced house was about 80-90k, now you'll be lucky to get one for twice that.
The reason that the local communities are "aging" btw is because all the young people are moving away! Because the gap between earnings and house prices is so much. Funny to blame that on the low earnings alone when it is the house prices that have ballooned.