Many people have made the same argument before. Every single time, i have the same answer: Your playtime and your penance points, accumulated before the penance update, are almost entirely irrelevant.
You would get pretty much all of those 2400 points while working on the new penances, if you had started playing after the penance update.
I saw your original post, where you said that you do not think that i am aware of how long those penances take.
I am now telling you, that out of all people on this forum, i am probably the one person who knows best.
See the full breakdown below:
I said that it takes around 200 hours. That is not necessarily quick.
It takes 200 hours if you actually play all 4 classes somewhat equally and swap your builds, when necessary.
Many people do not care enough about the penance rewards, to pay attention their map selection, in order to play the maps somewhat equally.
People do not usually care enough to efficiently clear their class penances, if that requires them to stop playing their usual build for a while.
And those who have the armor, do not necessarily wear it.
For example, i have it, but i only wear it on my ogryn, which i rarely play.