Basically it's because of Pornhub.
In Japan, it's hard as fuck to get porn for free since everything has to go through the government certification to prove all the dicks are blurry enough. As such, more people are forced to buy their porn and studios are able to make a nice profit even with relatively weird or niche fetish stuff.
In the West, however, only absolute morons pay for porn, so the porn studios have to mass-produce generic content that can reach as many morons as possible in order to turn a significant profit. Thus, the standard "I'm the pizza delivery guy, here to clean your pipes" setup in 5 minutes, 10 minutes of panning around the girl's body as she giggles uncomfortably, a 10 minute long series of spliced together, really bland blowjob footage with extremely obvious scene cuts, and filling out the remaining time with shots of the actors fucking (or in some cases just bumping together without actual penetration because they need to hide that the guy is a quick shot) in the only five positions that either of them seem to know exist before the guy pulls out and grunts directly into the microphone before dribbling a half-ounce of watery cum onto the girl's cheek.