It's obvious that ICS for the Nexus S 4G is not available right now as 4.0.4 isn't even complete. So, Chrome is not available to you either. You weren't lied to in any way.
If you seriously think that HTC and Samsung will not screw up the ICS update in and that it'll be stock ICS like the Galaxy Nexus has, I think you need to go back and look at their track record. OEM versions of Android won't magically change in any way with ICS. They'll look the same, behave the same, and overall, be the same because it would be pretty jarring for non-power users who have those phones to suddenly see the ICS GUI when they're so used to Sense/TouchWiz/Blur/whatever LG has.
You can either root your phone and get ICS, then go back to stock for the OTA if you want, or, you can enjoy it for the OS you have now. Never buy a phone just because of future updates. Always be sure you're satisfied with the OS your phone ships with because you never know how long you'll have to use it.
I think a lot of NS4G owners are simply starting to act spoiled and entitled. Sure, you were told you'd get updates as soon as humanly possible and that has been and still remains true. They're still working on Android 4.0.4 right now so 4.0.5 is nothing more than a rumor. Bugs happen and they do exist. If you want a buggy OS, then go flash an NS4G ROM based on T-Mobile's 4.0.3 and see how much you'd wish you waited.
You aren't owed anything. Not to mention you paid for a phone that you can literally customize to your heart's content. Neither Google or Sprint will stop you. Go do that.