This is about right, in my opinion! Most of us will have hundreds and hundreds of blades in the collection. I’m all for getting a decent return on your investment, but I could not be bothered corking blades that I buy for less than £10 per 100 in order to get further use out of them. It’s also odd in my view that the same individuals doing anything they can to get 50+ shaves on a single DE blade, will be happy to drop £100+ on a brush. I don’t get it.
It's not about money. For me, I know there is a series of about 60 exquisite shaves after the first 10 or 15. They are butterknife smooth, but almost the same efficiency as a new blade. The actual number varies with the type of blade and the shaver's skill, etc.
The only thing I do is rinse and flip the blade after each shave. I've always done that. Preparation and technique are the key variables. The other stuff you mentioned doesn't work to any great extent on modern blades.