Yep, so something like miami pest control.com is something I'd get the domain for just as you mentioned city + niche.com. I use .site a lot as it's cheap and useful for scaling. I can buy 5-6 .site domains vs 1 .com. I don't really like the SEO pitch cause it's harder work, they just care about business. You give them leads and they convert them they make money instantly and not in 6 months time or moan that nothings happening yet they're paying you x a month or so. You give them a roofing lead and it's from someone who needs a roof replaced that might turn out to be a $10k job for them. It's tangible. Everyone knows what a lead is.
If you're using a network then scaling is easy, no need to do sales etc. just rank a new site and make money.
I defo. agree with you to a point but lead gen./rank and rent is nothing new, plenty of people and gurus talk about it and sell courses etc. it's been around for ages. I find a decent keyword and build a simple site and rank it. Nothing special technique. It's the keyword research that I have an edge on which I'm sure not many have the same experience/knowledge to find the sorts of local KW I can find. That I don't share, I have a big long process for that and no one really knows the method I use to find the absolute best keywords that can't be found on KW research tools.
It's a heap of manual work as well so hard to scale effectively, I have ideas on tools I could make to automate stuff but yeah it's a heap of manual work. Plus even in places of less than 25k pop. you can make a few hundred dollars a month. There's 4115 cities between 10-100k pop.
As I mentioned I only sell to network BUT the best way of selling local is free leads, since it's SEO traffic it cost you nothing (just lost potential revenue). Maybe 5 free leads or free leads for x days. If it's a niche with decent margins and high price then even converting 1 new client a week could boost revenue an extra 6 figures a year. Think about something like roof replacement. If they get a job for a few thousand dollars from one of your free leads they'll see the value and be happy to pay.
I let it index for a bit and rank, maybe 1-3 weeks. Then maybe 2 links a month, 1 a week is a bit of a push initially but ok. You can build up as you go but if you're targeting easy terms you shouldn't need too many links. Might take 3-6 months to rank, maybe sooner.
I use a network as mentioned but if not then the best approach would be to approach those perhaps that are ranked on page 2, going through map pack results (not those in top 3 though) and yelp etc. pick companies that have decent reviews as you want to make sure you're sending leads to good companies.