Staycation - 'stay at home vacation', that's where it came from.
I do not live in Cornwall, it is not my home - therefore, if I go to Cornwall, pack a bag/suitcase, stay in a B&B (at cost to me), and visit tourist attractions there, I'm on holiday (or, to keep the language similar, I'm on vacation) - I have travelled away from my home and incurred the expenses associated with travelling away from my home address.
I do live in the Midlands. If out of, say, 7 days annual leave, I plan days out at local attractions/tourist 'things', eat out several times, do the whole 'be a tourist where you live' thing - as I am not planning a holiday (vacation) this year, so no accommodation costs above my usual rent/mortgage - I am having a 'stay at home vacation', a staycation. I am spending my annual leave doing enjoyable things in my local area, that I might not ordinarily do (for whatever reason), but with no accommodation costs to me.
I admit to being a pedant, and I'm actually pretty open to language changing and developing generally, but syntactically it doesn't make sense for a 'stay at home vacation' to take place anywhere other than your home property, surely? And given the past 18 months, we are all well aware what 'home' means...
Domestic tourism is the term for holidaying in your own country...as opposed to international tourism...that just makes sense...