Live rock can be brought back to live.
Live rock in my area starts out $7lb for base, and up to $9lb for figi, or tonga. and other rock is still even more. $12lbs. So I can understand not wanting to spend that much on rock.
That is why you need to be creative.
Last year I got a 180gal tank, I knew that it would tank alot of rock. a least 250lbs. and at $9lb, it was going to run me well over 2 grand. So I ran an add in the local "Thrify Nickle" type paper. and ask for any unused live rock. I had know that a little over a year before the last LFS in our area had closed down, and most people didn't want to drive 40plus miles to get supplies or fish. So alot of people packed up their tanks, or just went back to fresh and put the live rock in the garage. So in my ad, I even told people that if the rock had been sitting in the garage for a year dry, that would be ok. You would not believe the calls I got, for over two months I had people calling me. Asking me to get that crap out of thier way. By the time all way said and done. I ended up with about 300lbs of live rock, a 75gal tank, a 50gal tank and a 29 gal tank/ with fish that were in desprate need of help. When the LFS closed down, there were so many people who didn't know what to do. The guy at the LFS always told them step for step. And the info he gave them wasn't alway for their benifit. He make quite a bit of $$ and retired in Greece. Must be nice. Anyway.....
I got all of this ROCK, and put it in the tanks that I aquired and threw a couple pieces of live rock from one of my tanks I have had running for about two years at the time. It took about six months, but by the time I was ready to set up my 180 all the rock was cured. Alot of the rock had little red, yellow and blue feather dusters. I know this had to be from the rock that I got from the add, because none of my rock ever had those. I also ended up with a blue sponge. and a gold furry thing. might be a sponge, but I think it might have been golden rod. I can tell you my tank that I had running for two years never was so blessed. The plus, this rock only went thru and very short lived alge bloom, about 1 week. Cost for all the rock. Zero dollars. Just a lot of elbow greece cleaning it up. and patients and praying it would work.
So the answer to your question is a 100% possitively, absolutely YES!!!!!! You can bring live rock back to life.