Indeed.. Mostly-static pages with sprinkled-in interactivity were fine (like a table where you could sort the columns), but a full app? I dread having to touch the one page we have that uses Backbonejs+Mustachejs.

Also, things like unidrectional data flow are generally considered normal now, but back in that era it was rare. Two-way binding was much more popular, with constant bugs as the app grew. Around 2013 or so I was trying to switch a new page we were building to a very simple form of unidirectional data flow to deal with constant issues (ours issues were mostly losing state, we were all ad-hoc and not using two-way binding) and the other devs just did not at all understand it, constantly sidestepping it without even thinking because jquery made it so easy to touch everything.