Mike,
Pre-filled hydraulics are designed to be just that type of approach to the problem, remove, replace, invoice and drive away. Notice the word invoice.
Depending upon the situation, this option is a good one.
I am just suggesting the possibility of determining the real problem and trying to fix it.
DOT 3 doesn't evaporate to my knowledge, if it has gone down in the reservoir, it's gone somewhere. The fluid level will actually increase in the reservoir as the clutch disc gets thinner.
Pumping to get release, sounds like air in the system. Did it come from contaminated DOT 3 that now has enough moisture content to create steam (air bubbles) under high heat and cause no release? Unknown.
I have previously posted about techniques to test our hydraulics and it only takes a steering wheel puller to get feedback w/o using the clutch to provide the feedback. Isolate, analyze, diagnose and then repair based on the testing.
This might help.
YouTube - perfectionclutch's Channel