I think you are incorrect. Watch this video. The all seasons actually brake better in dry and cold conditions than the winters. I have seen several tire tests in dry/cold conditions like this and the all seasons win out in braking every time.
The same has held true for every UHP Summer tire I've had on any car. I have UHP summers (currently Pilot Sport 4S) and dedicated winters (currently Hakka R2). For two decades now, over many different sets of tires, I put off switching to winters as long as I reasonably can because all the radio ads saying "winter tires are better in all situations below 7C" are just wrong. The moment I put my winter tires on my braking performance in the dry goes to crap by comparison (even with 'performance' winter tires), and wet is pretty close down to about 1-2C depending on the UHP summer tire. Wet, I found Michelins were good down to almost freezing, while Toyos fell off around 4-6C. Bridgestones were in between.
I would not doubt that all season or even UHP summer tires are going to win a
dry braking contest down to freezing, and even well below freezing depending on the UHP tire in question. The sipes on a full winter tire bend, fold, squirm and make lots of noise causing a disconnect between wheel and road when it's dry. Some are better, some are worse.
Now - I do my own winter tire switchover in my garage (no appointments at shops necessary), I watch the 14 day forecast very closely this time of year, and especially post-COVID my "daily" vehicle use is generally light, close to home and predictable. If any of these things weren't true I wouldn't hold out so long. Or I'd consider having three sets of tires. My winters are already up in the garage along with the tools, aired up and ready to go on, but I'm probably holding out another full week. For someone whose car I take care of but doesn't live with me - I put their winter tires on last weekend. They drive farther, have less predictability, and can't change plans and mount tires with as little warning as I need.
To each their own. I believe I'm keeping my family and those near me safer
based on my situation. The 7C message on the radio is just wrong, but if it gets more people to buy real winter tires we're all safer and I'm all for it.