Here is how it works based on sites we have released recently + a couple that have ran awhile.
Assuming its a new site using all out Schema.org as well as fallback data-vocab for crumbs and reviews datas, you should expect at least a 3 month lag time. You will see the Google webmaster tools schema reports doing nothing -- no new reviews, no new pages....even spikes then drops in counts or false alarms. Dont worry its just GADHD. One day in month 2(ish) you may see all the counts start fill in, level out, and stabilize. You may see the fallback data-vocab SERP widgets activate on trafficked/fresh pages. A month from this point, the schema.org SERP widgets should activate assuming there are no errors in GWT. You may notice back and forth, especially for reviews, price, etc during this time. One day they will be on, another off. One query on, another off. Eventually the SERPs will stabilize, but its possible that not all will activate in SERPS for all queries/views/etc.
As closetnoc pointed out in a comment for original question, the RDF triggers from fresh focal data/pages. It may take much longer than 3 months for those buried pages that never get hits, possibly up to a year for the really stale ones. Its a good idea to freshen up the areas that you want to trigger rich SERP widgets. Google will show they are indexed-RDF in GWT, ready to rock n roll, but the actual SERP widgets will not activate until the trigger allows. This trigger is fresh/traffic/interest/searches to your "already indexed" RDF pages.
Just be patient and expect to see alot of fluactions and inconsistancies. Thats just how the RDF bot index rolls with the prediction engine + pop queries I guess.