Previous to this change, and for as long as I can remember, FAA charts depicted a note telling pilots to refer to current Canadian charts and flight information publication publications for information in Canadian airspace.
It may well be that ensuring the accuracy of foreign aeronautical data was becoming an issue for the FAA and there may have been liability concerns. From practical point of view, charting aeronautical data in foreign states is not the FAA’s business and there is arguably a cost involved with tracking and updating foreign aeronautical data to be charted.
What is very unfortunate, though, is a lack of uniformity between chart products developed by different ICAO states, and ease of getting them. Canadian charts use some different symbology and don’t use magenta color like U.S. charts, but are relatively easy to get. Where would your average recreational pilot get a VFR chart for Mexico, Cuba, the Bahamas, the Dominican Republic, some of the other Caribbean countries or Samoa? In Europe, many VFR pilots seem to buy charts produced by private companies, just like IFR pilots tend to use Jeppesen or Lido charts when flying internationally. This helps address the commonality and supply issue, although there is typically a higher cost involved than buying “official” charts.