With hindsight, sure, but was that really obvious in 1995 when JavaScript shipped?
1995 saw Java's first public release. PHP was a CGI-thingie that powered Rasmus' personal homepage. Tcl and Perl was the state of the art of scripting languages. Ruby was released (it would be another four years before it started getting traction outside Japan). The first edition of O'Reilly's "Programming Python" was published in 1996.
Functional programming is barely mainstream today, it certainly wasn't in 1995. Netscape had enough on their plate convincing people that "the web" is a cool thing and they should be on it without driving a programming paradigm change at the same time.
Seriously, it's 20 years ago. You're operating with extreme hindsight.
1995 saw Java's first public release. PHP was a CGI-thingie that powered Rasmus' personal homepage. Tcl and Perl was the state of the art of scripting languages. Ruby was released (it would be another four years before it started getting traction outside Japan). The first edition of O'Reilly's "Programming Python" was published in 1996.