Steam sales have lost their luster. Between the broadening of PC game platforms with similar discounts (GOG, Epic, Origin) as well and the reliably cyclical nature of these digital discounts on said platforms, the Summer sale--or any sale for that matter-- has lost all sense of uniqueness and urgency. I have seen nearly all of the games on my Steam wishlist on sale for great deals, and I know they will be back with even better deals down the road.
Couple that with a bulging backlog already existing from prior sales and Humble Bundles and you get to where a lot of people are today.
As with Insanolord, the Switch has an exemption in my book, but it has even dampened my purchasing there as well.