I think the problem is that it presents a very unconventional method of training... one that is incompatible with a busy training airfield with a tower and 7 planes doing Prince Edward Island sized circuits... and hour building instructors and money grabbing FTUs who are interested in you purchasing the most dual hours possible.
When I did my float endorsement... the first lesson didn't even involve flying... it was launching and docking (good luck going through 112 items on the typical FTU checklist when you are drifting towards pilings

), displacement taxi, sailing, plowing, step taxi, etc etc... Any time you are learning to fly an aircraft where the primary difference is how it behaves on the ground... you should spend most of your time there.... rather than burning off 6-8 minutes in a circuit for 30 seconds of actual learning and experience.
At my home airport... we are perfectly set up to do lessons like Cat Driver suggests.. no tower, minimal traffic except for summer afternoons and sunny weekends, mostly rural/industrial areas surrounding, and I work for the airport operator. Even if the airport is too busy, we have two other airfields within 15 minutes of flying that are suitable for the same thing. We also have lakes suitable for ski and float flying, gravel bars, and some challenging mountain airstrips.
Also.... since my summers are pretty much a write off... unless Cat Driver has other plans I'd rather have the plane rented for the whole summer for solo time building. Go down to California or Florida, head across Canada, go up the Alaska Highway or to the NWT with a stack of resumes and kill two birds with one stone....
You probably aren't going to find many opportunities like that in Canada...