The idea they have been holding back for 8 years is wrong. IE7 came out in 2006, that's 3 years.
As is fairly normal people didn't switch to another browser because they were happy with what they had. They just haven't updated their version in 3 years, which is pretty normal with other types of software.
And does this mean we are going to drop other browsers that have had replacements 3 years ago or more? Like Firefox 1.x, Opera 8 (version 7 is on the Wii), Safari 1.x etc.
No, but for large windows installations based on active directory it's the only one they can easily manage. Other browsers need to provide an MSI installer to make it easy, though after 5.5 years of asking, Firefox still doesn't have one:
And before you say but it has to have proper support, yadda-yadda. They're an MS Certified Partner and an established company based in Pennsylvania - if the MSI is messed up you should be able to sue them for losses or pay them for support.
I've never used nor do I have connection with this company - caveat emptor.
As is fairly normal people didn't switch to another browser because they were happy with what they had. They just haven't updated their version in 3 years, which is pretty normal with other types of software.