This is the complete opposite of having a master format.
When "we" as a group cannot agree on even basic things such as whether to use xml style tagging <p> verses troff-style "implied markup via teletype-style visual formatting plus various escape clauses" and if "we" cannot even agree on the worthiness of keeping page numbers or not, and when "we" have 30,000+ old files which I don't see anyone volunteering to rewrite in "master format" not to mention put back in page numbers, then I don't see any chance of a "master format" working. I do see merit in making this suggestion -- if you are the person who seems themselves as being "the master." But even then the suggestion lacks merit because PG volunteers are not forced slaves, nor are they stamp-lickers. If they don't want to do it, they go do it elsewhere, or they go do something else.
This is so 90's, so `me´-generation, so Girl Scout Merit Badge. I want *my* name all over the place, I want *my* bragging rights, I want nobody to mess with my work because I'm the paragon of evolution.
This is simply excuse-making for failing to take a good hard look at the epub and mobi which PG is currently providing customers, the great majority of which files are barely readable on those small machines, to put it kindly, whereas other organizations ARE providing high quality highly readable epub and mobi files to their customers, and are doing it from PG source files, and are often doing so without spending a huge amount of time fixing up those PG files. If you and/or the WW'ers can do it, then why pray tell have you not been doing it? The truth is PG is having its own version of the problems DP has been having: namely a small number of old-timer insiders are more interested in having the power of being "the dogs guarding the straw" rather than providing real books for real customers to really enjoy reading.