Skyscrapers are huge investments, and the ones who build, design and own them are held responsible for their safety. So extensive amounts of time and money have gone into engineering these buildings to last hundreds of years.
The only unplanned collapse of a skyscaper were the World Trade centers on 9/11. Otherwise, there has been no collapse of a skyscraper. So you should feel just as safe inside them as you are inside your own home.