It's kind of refreshing how all the adults in this manga willingly acknowledge that the rules about porn and sexy stuff (especially the age limits) are STUPID.
And at the same time they assert that we gotta uphold them, because that's society for you. No matter how hypocritical or contradictory it seems, you gotta go through the motions.
I think most people working in a particular industry have a front-row seat for all of its silly idiosyncrasies, so it's not surprising for porn industry professionals to recognize the obsolescence of its institutions. On the other hand, all institutions, no matter how obsolete, have perceived and real value, which blend into each other: the perceived value comes from the fact that, as humans (especially as we get older), we instinctively defer to long-lasting institutions, assuming on faith that if they've survived this long, they must be doing something good. While this assumption can and should be challenged, the other big part of the real value of institutions is their facilitation of low-friction interactions in social environments too complex for any single person to penetrate. In other words, challenging an established institution (like the age restriction on porn) may have cascading side effects that will negatively impact many more people beside yourself. For a society like Japan, which had learn to coexist in a very limited physical space for a long time, the risk that rocking the boat this way has historically posed to its survival just consistently seems to be judged as not worth it.