Five years ago all the vehicles with LS engines were still relatively new. So there were far fewer people modifying them... Some because the vehicle was still under warranty, and others because word really hadn't gotten out about how easily they can make power and how much power they can handle in stock form.
Flash forward five years, those LS vehicles are 10 years old, plenty have been totalled and put into salvage yards. People have driven past their warranties and are more willing to modify their engines. And a decade worth of aftermarket parts exists now. And a decade of reputation has been established.
Of course the price for a LS motor has went up substantially. The demand for the LS engines has skyrocketed, because a lot of people want to fix their Fords. Lol. But seriously, you can find swap kits for any vehicle imaginable, and word has gotten out about 15psi junkyard turbo builds on stock 4.8/5.3 motors pushing 400+ horsepower to the wheels and lasting over 100k miles.
What is not to love about that? Of course everyone wants one in their miata/blazer/celica/bmw/mustang...