The multitouch trackpads actually showed up in the early 2008 MacBook Pros that were the last ones before switching to the unibody enclosure (IIRC the keyboard/trackpad parts could be retrofitted into 2007 MacBook Pros). The early 2008 models still had a separate physical button at the bottom of the trackpad. The late 2008 models got rid of the button and made the whole trackpad hinged at the top to act as a button. Then in 2015 they introduced the Force Touch trackpad that fixed the awkwardness of needing more force to click the further up the trackpad you went.

Yep. And this blog post from 2009 was a big inspiration for me in exploring touch on the mac: https://archive.org/details/2009-03-28-steike-code-macbook-m...

and a comment a few years ago by me: https://news.ycombinator.com/item?id=23274577