I imagine that folks would have cottoned on to the advantage pretty quickly. And those that didn't … I guess they could have always become telephone cleaners or something:-)
Did you see the '(set! (inner-html (get-element-by-id document "demo")) "Hello JavaScript!")' bit? That's DOM-handling in Scheme. Not a really great API, but it's not terrible either.
If JavaScript had had Lisp syntax, then everyone would still be using Flash. Or some other plugin that provided a language with a more popular syntax.
IME it's a learned thing from only knowing languages that at least superficially resemble ALGOL.
JS is a first language for a lot of people - because their goal was to make a website do something. Scheme would not have been any different.
IME many computer programmers learned Lisp in college and for some reason hated it–I think in part due to the syntax and in part because they had a hard time with recursion and other "mind-bending" concepts. They often still harbor an irrational precedent to this day.
Me, on the other hand, I loved Lisp as soon as I learned it. (Perhaps I was primed by having learned APL in high school.) I changed my major from Astrophysics to Computer Science because I felt that SICP was even cooler than black holes and neutron stars.
If people disliked the syntax enough to avoid the language (and the browser that uses it), I imagine that other browsers would've started supporting other languages, and something else would've dominated.
In IE world, things were actually even crazier, because the whole scripting story was extensible (via Active Scripting). So you could use Perl, for example...
Not to mention that there were other ways to execute code in the browser in those days. We have 'no choice' but Javascript today simply because it's the option that people eventually gravitated towards, forcing the others out of the market.
The original suggestion was that people would use Javascript, or any other language in its place, simply by virtue of it being the only option. I argue that the wrong language would hamper adoption, and eventually some other language – like, say, VBScript which came only 6 months later – would have taken over.
Javascript persisted, and eventually completely dominated, because it was good enough. A language not good enough would have not had the same success, even given the otherwise same environment to grow up in.