caveman, your cute ways are lost on me ;-)
These statement say the same thing, just in reverse order. Google wants stable and fast results, maintenance of the database is a secondary consideration but one that remains important.
I have experience building a LVDB and have spent many hours reading on the topic. Some people don't have anything close to that experience, yet seem to be experts on how they are constructed.
And you seem to be confusing the "supplemental" index with my thoughts on how google works. To be honest, I am not sure a "supplement" index or database actually exists. When I see "supplemental" results, these appear to be pages that no longer exist as they once did and are marked as such in a database. Old pages or pages of questionable quality, that's all, that are returned to the user as a last resort.
Again, on the topic here:
Does the "sandbox" Only Affect Phrases Containing Popular Words?
If the phrase has no words over 70-80 million results, does sandbox apply?
Intelligent people would never build a search engine that looked at word frequency. They would look at query popularity or frequency of query. The sandbox is about returning quality results on frequently queried terms, not frequently appearing words.