That curve is indicative of a lot of miles. That is not a catostrophic failure event occuring but the normal wear process. Is it desired? No but if you maintain the lifter location integrity, they could run for another 100k miles.
The so called metal coming off of them, is not anymore than a normal running engine..
Now there is a flip side to this, if you end up needing new cam bearings don't use the old cam ans lifters. The work to replace the bearings is the biggest part of the project not the cost of a new bump stick kit...
If you do need cam bearings I would roll in new rod and main bearings. You May even install new rings and ridge ream the bores if needed.. If it doesnt use any oil just install new cam, rod, and main bearings along with a cam and lifters..