First of all, wrtitting the story and selling it can face real legal consequences. This "industry" is not an isolated island. Look at how many "real porn" html novels are spamming this days, some using Youtubers as avatars. It's a matter of time til one of those porn companies or individuals sue the creators. It's a clock ticking that is about to happen as the "real porn novel" is starting to spam.
Second, if you portray a real world scenario, not scifi spaceships, medieval orcs, magical creatures, etc... When we look at that world, we aply a minimum of real world logic.
Why are all this FMC novels start with convenient isolation? Why? Because its needed. Every AVN start with "a couple moved to a new city and they dont know anyone there" (except for a convenient token character to corrupt the MC). You dont blackmail a real bimbo with a phone picture in real life unless you are an absolute idiot. Every bimbo you know is a phone call away to bring to your life a bouncer and 5 of this friends to "paint you the face". Every bimbo you know is a phone call away to talk with really dangerous people and ask them for a favor, and trust me, those guys are willing to charge for the favor so they will gladly overcommit. Every person you know has a familiar who works in the police, or lawyer, or politician, or military, or ar part of a boxing gym, or its involved in drugs, etc... And every woman keep a fair share of those in their phone's agenda. So isolation is required for her to be helpless, otherwise none of her options makes any sense.
The authors know that its stupid most of the situations but at least they try to build an excuse. And that is because they somehow have to obey to real world rules because its a real world based scenario.
If a 35yo woman has sex in her visible backyard with a 13yo, and someone spots that, police enforcement are going to ring that door soon. I'm not a 16yo, as an adult I know this is part of the situation and I cannot ignore it. And also, the MC is an adult, she shouldn't ignore it. Between 18 to 30 you will see a lot of legal shit in your life (unless you dont leave your computer at home), and once you experience it, legal consequences are not something you can ignore anymore. But, once again, I'm guessing this industry is a bunch of 16yo incel dudes faping like if there is no tomorrow.