Fromsoft's difficulty is a core mechanic of the game.
And if all you are asking for is slightly reducing damage, you'd still have to deal with the same mechanics as before.
I didn't say "slightly", but it would surely increase the emount of people that are able to get through the game. Also, at least for me, no mechanic was as frustrating as the amount of damage enemies deal to you.
I could imagine that in a parallel dimension where Sekiro shipped with 50% less damage from enemies, people would still be asking for an easy mode, because they'd still have to deal with all the mechanics of the game.
For sure, everyone can never be pleased. Some people will be asking for more no matter what the developers do, does it mean they should not try to improve anything in their games at all? Should they not have made Sekiro because some people didn't like how different it was from Dark Souls?
this is a game that not only won multiple GOTY awards, but sold very well according to "did not meet expectations" Activision.
I don't think anyone is arguing that FromSoftware is in dire need of more money, but getting more people to buy and enjoy the game would never hurt.
And frankly if that damage change is all you need to enjoy the game more, just download cheat engine and make it happen. Or get a mod, there are easy mode mods out there by now.
Or people could request it as a feature from the developers? ¯\_(ツ)_/¯
You'd still have the original difficulty to challenge yourself so there's nothing you should worry about.