I agree OEM parts can be expensive, but you are pretty much guaranteed they will work properly. Some generic Chinese parts are OK, but some can cause more damage or problems with the printer because they don't work properly. If you get a cheap captop an it doesn't seal properly then the head can dry out and block and not be recoverable.
If you have a printer worth say £5000 it doesn't make sense to use cheap parts. Replacing parts should be part of the regular servicing, and something the business should cost into their normal overheads.
I would be interested to hear more about your method of fixing delaminated heads? To be honest in all the years I have been a tech I have seen very few faulty heads that are due to delamination. Nearly all are either electrical problems, or they have blocked beyond saving. The only delaminated ones I have seen are very old ones that have definitely made their money already, so replacing is due