I also noticed the slower selling trend.
I think the economy is a big factor. Housing prices are tanking. Many people became rich in this country due to the booming real estate sector in the past. When the sector cools down, they will have less money to buy luxury things, such as expensive coins. Same for people in the oil industry.
Also, Canadians are more in debt and paying more taxes this year. My bi-weekly paycheck is $300 less this year, because I'm forced to contribute more to the "enhanced" Quebec pension plan.
Personally, I could afford any coins that cost less than $10,000 in the past, thanks to my part-time gig. However, I can no longer do so because I recently ended that gig.
I noticed this year's coins generally have lower mintages and higher quality than those in 2017 and 2018. I give a thumb-up to RCM
for doing this. Hopefully, more collectors will start to purchase coins soon.