Yes, I understand what you mean. Also, I didn't say it was better, I said maybe better but eh, that's just my opinion. Now, I'll rebuttal a couple of your points
I think Speed Champions does have some playability, it's just both of us have grown out of the age demographic that this playability is meant for.
Per the Speed Champions website "Lego Speed Champions children's toys feature authentic, realistic, buildable cars from iconic brands such as Bugatti, McLaren, Mercedes-AMG, and Mercedes-AMG Petronas Motorsport, plus all-new Ferrari, Ford and Porsche models. Car-mad kids will love building beautifully detailed LEGO brick replicas of classic cars, sports cars, endurance cars, iconic cars, and race cars, and then playing out their driving dreams as they compete against friends to be first past the finish line"
As Lego is trying to be authentic and realistic with these cars, a pullback motor would just ruin the look of a car and probably not want to make people buy it because of how unlike the car it looks.
If you want cars with pullback motors, go and look at some of the $20 Technic sets, as those have basically become the new Power Racers. For example, BASH and WHACK (yes those are their names) which were just released this year are cars which each feature pullback motors and the ability to break apart slightly when they crash into one another. Then there are the two stunt vehicles from last year, Stunt Bike and Stunt Truck which also contain pullback motors and a ramp, similar to Monster Jumper from 2009. There was also a hot rod and police car in 2016 and a quad bike in 2015 which all contained pullback motors. Heck, we're even getting another police/getaway vehicle combo again in 2019. As you can see pullback motors aren't dead, they've just become a part of Technic instead.
Also, as I stated in my original post, I would really love tiny turbos to come back, but they don't really have a place to go atm, as I don't think they can be detailed enough to be considered Speed Champions sets, and if they're built like they were before, they wouldn't really fit under Technic either.
Finally, in regards to RC's, Power Functions/Power Up is basically the modern equivalent of it, so that's also not really dead