There is simply much more software work to be done than hardware work. Pretty much every company running a real business has some software presence on their staff, whereas the presence of people with an EE background is quite rare by comparison.

Hardware design work is hard, but you usually only have to do it once for any given component or any given product. Most of the parts I use were already well-established in their markets over 10 years ago. (Although whether they'll still be around 10 years from now -- or 1 year for that matter -- is a very different question.)

Conversely, a web developer's work is never done. There is always another web site to build. Failing that, someone always wants to do another gratuitous reskin of an existing site, just to keep their users from growing complacent.