The same is also true within the Macbook line. The 14" Pro is smaller and nearly 2lbs lighter than the first 13" unibodies. I have my 2009 college laptop on a shelf as a memento and it feels pretty chunky. This hasn't changed much in the M-series though, and the M5 is slightly heavier than the M1.

Something I miss from the Windows side is sub-kg machines, at least since Apple discontinued the 12" Macbook. It makes a surprisingly big difference when traveling, especially with Asian carriers that have hard carry-on limits. The Thinkpad X1 Carbon is a fantastic form factor, though the older Intel chips run incredibly hot. I repurposed that as a garage/workshop Linux machine. Unfortunately, the price differences between Mac/Windows also disappear when you start looking at those higher-end machines.

My Sony Vaio Z from 2009 or 2010 looks at your Dell in contempt: 13.1" FullHD screen at 314mm x 210mm (we'll pretend the thickness does not matter ;)) and 1.36kg. Vaio TT was even smaller footprint.

But even in 2018, you could get an X1 Carbon at 1.13kg and 323mm x 217mm x 15.5mm.