language is not static, though some words do have long, enduring, meanings. Words can even have many meanings at the same time. I also agree with the very last sentence of your author's summation.
try substituting "standardized" or "made ready in case needed" for "well-regulated" in the sentences you gave as examples. most don't really make sense even in the context of the time in which the sentences were written.
the sentences from 1709, 1848, and 1862, don't even have the same context. they would be examples of words or phrases having different meanings at the same time. those sentences have to do with individual well-being or mental acuity. the sentences from 1812 and 1894 also have different contextual meanings. they are related to something that runs in a controlled and efficient manner.
so, please remember, context is just as important as etymology.
In a political context (I will remind you that the constitution is a political document) we should use the political meaning. this is just as important as knowing the vernacular of the time. And, the vernacular of the time included the definition of well regulated being, "To control or direct according to rule, principle, or law."
For further context, the revolution was a direct response to the tyranny of the King. the constitution was an attempt to constrain government and it's appurtenances. thus the second amendment was meant to constrain the ability of the military to inflict its will on the citizens. the forefathers wanted the citizens to be free from the indignities that a tyrannical government and it's unchecked military could inflict upon it's citizens.
Also, you define well regulated as, "to be kept in a regular state of preparedness." But your example defines it as, " the property of something being in proper working order. Something that was well-regulated was calibrated correctly, functioning as expected." Two completely different meanings to be used in different contexts. We need to define it in the context of the second amendment at the time it was written.
If well regulated meant what you seem to think it means, then the uproar on DP about the changed wording of the second amendment in that textbook (that has been talked about on DP)would be based on false indignation. For the changed wording in that textbook would support your argument. you seem to think that a well regulated militia is one that is standardized and ready to be of service when called upon. that could be argued to mean that you only have the right to have and bear arms if you are in the, or a, militia. anybody with half a brain would know that that is not the case, hence the uproar. you sound more like someone that wants to take away the right to have and bear arms from any citizen that is not part of a militia. you sound like a gun grabber more than a liberty loving patriot.
I would also point out what beersnob stated in a reply to one of my earlier postings. the SCOTUS agrees with my interpretation. Not that I am much of a fan of the SCOTUS, but I do have that to support my argument.
Lastly, and with all due respect, I hope this helps you in your understanding of the second amendment in the proper context.