Depending on the customer i use eclipse, vs, sharpdevelop, netbeans, cloud9, sublime+plugins as ide, with svn, git, and whatever "pattern" they came up with one day.
FF/chrome allow you to test stuff in context, and fiddle with it.
If it runs in FF/chrome, these tools are available. No need to wait for a system/file right, firewall rule, svn update, whatever.
These tools are for fiddling, bug hunting/understanding and prototyping. If you start to do "real" development with them, well, I wish you good luck sir...
moreover, these 80' tools you speak about, i know them (oh can i forget). Depending on the user you logged in with, you were in dev mode or user mode. These wtf generators have, imo, nothing todo with modern stuff, which expose internals, so you understand what happens.
On the same vein, there are "simple" online webeditor, or even confulence wiki that use the same tool for usage and admin. And what about jsfiddle, and other online ide, that use the client as an editor for another language?