Seems to me that laser rot was finally traced to one asian pressing plant that did not sufficiently filter the water used to wash the aluminum surface before it was pressed between the plastic. Once that was "solved" the problem was licked for new discs from that source.
I can't say. Defective pressing plants (and there were numerous companies that used them) have been identifed in the lore of LD.
Even Criterions Plus $100 releases (retail) were prone to laser rot. Not all discs were, some plants were bad. Don't know if it was glue, loading docks, etc.
It is real. Some have already claimed to witness laser rot in CDs and DVDs (visible holes that impair playback). I believe that would be different because a laserdisc is essentially an LP sized CD glued to another LP sized CD. I have seen a few bootleg CDs that were "double sided" but have not seen this as any sort of industry standard. Some believe that poor sealant, etc. led to laser rot at some companies.