I have noticed something over a period of many months or over a year. The ATMs that dispensed $5/$20/$50/$100 bills were frequently out of service (as in likely constantly breaking down) and since $5 bills are used heavily, having a tendency to wear out much faster than the other existing denominations, even with Polymer - though slower than with the cotton-paper version - and therefore causes the machines to break down more often. The banks experimented with the Polymer $5s, it did work for the short term, and now it appears it doesn't seem to work well with ATMs and most likely in-branch secured cash dispensers. Rather than face frequent repair bills, the Scotiabank realized it's a lot cheaper to load the ATMs with $10s instead of $5s than to face mounting repair costs. $10 bills seem to last longer because of their lower demand and they do not get passed through so many hands.
Since nearly all bank branches rely on cash dispensers and multi-denominational ATMs, I suspect the number of $5 bills in circulation have likely reached their peak, and it will be a matter of time before we see the number of $10 bills reach or surpass numbers not seen since the 1980s. There will probably still be $5 bills in banks, but likely only available for commercial transactions.
Also, I have not seen any new $5 bills this year so far (I saw INM/INN prefixes late last year and last I saw on the SNDB, the high and low for the respective prefixes were reported from my province; but after that, nothing). Maybe this is proof that the $5 bill's numbers have reached its peak and is on a slow decline now. Either way, it appears that $5 bills do not agree with ATMs and cash dispensers.
Maybe that could explain the Bank of Canada's decision to keep Laurier on the $5 for at least a few more years.