Nah, platforms are not only stylish but much desired by people who are vertically challenged, like myself so... I am always wearing a chunky platform. Heck, I want my boots to look like a semi truck's tires and grip like one. If you are living in a place with a lot of snow, they are especially not out of style. I was in Japan a few weeks ago and even during the winter girls are wearing 3 inch platform boots in the snow and keeping perfect balance.
If you do a quick search on SSENSE or Farfetch, boots are still being made to be chunky in their new season lines. So the style is still healthy! (I'll be wearing chunky regardless.)