The silver does not stick to the optical surface well. Think of as simple lite coating. First contact may remove it.
To be honest, they are exploring a path that may not offer the perfect solution to replace AL / sio2 for larger mirror.
I don't think this was the idea of the project in the beginning. The first step was to find a cheaper way of coating one's
mirror without costing an arm and leg and not worry about the shipping, do it yourself. This goal was completed. Next
how can we make last longer, weeks, months, may be a year or two? That's were the anti-tarnish came to be. This
seems to work OK. Remember the idea was to have the coating to last at least for the observing season and get
away from the high cost.
I have not seen or read an article on the life of exposed silver for telescopes (or other products), other than the old docs from 1800's. Once AL came to be, that was the perfect solution in most cases and live with it's limits. I think and believe they are totally alone on finding the best mix of solutions to extend the life of the exposed silver. Remember this was
a process to be used a bath/dinner room mirrors, protected by glass on one side and heavy spray paint on the back. So the silver we see is sealed. So issue here is not there is a solution (AL/sio2) but the cost of coating larger mirrors. I can imagine the thoughts of old folks like John Bashear and John Strong would be, chasing this once again.
So on less there is someone willing to fund a major project to see this through. It's going to be limited to what time and effort
to the folks who support it. Don't forget, they are limited to what companies can offer to help this. One year we may have a great product, the next not so, because it was not selling well and there was a lack of interest.
Again AL/sio2 was the solution.