Now do Black Friday, Back to School, New Year et al.

Hasn't this been common knowledge for ~15 years? In NZ there are laws to stop this, but the retailers just set their pricing high/low on the shoulder dates so as not to fall foul of the law.

Almost nothing is a Sale anymore.

All sales are scams. In the pantheon of sales gimmicks, especially hilarious were the Tri-City Sporting Goods "going out of business sales" every year. The only honest retailer is the one that doesn't do sales and charges fair prices all the time.

In Europe we have a proposed or existing rule (unsure as I actually see just swiss shops doing it right now) that you have to show the price development for a product over the past X months.

Amazon is almost always the most expensive option no matter if it looks like a "sale" or not.

Surely this is illegal