Another one bites the dust, have a look at https://www.dmxzone.com/go/33281/styling-elements-on-scroll. This is the replacement for Bootstrap’s Scrollspy. Can’t wait to rewrite the tutorial on parallax and adding a few more animations!
PS: Of course I am exaggerating with the subject line, but it caught your attention. 
Yes indeed - App Connect already have many of the Bootstrap components and much more, well integrated and also jQuery free 
Also as we are integrating much more core CSS functionality as CSS grid - the need of Bootstrap will become less and less.
I see Bootstrap more as a transition helper till the browsers get it right. Just like jQuery was long time ago.
So as the browsers progress together with the CSS standards, the need for frameworks like Bootstrap will become less.
But we are not there yet might take a couple of years