But you see the long sleeve and tie is more than just an "undershirt" to be worn under the tunic. It's perfectly acceptable office wear.
And while long sleeve by itself is not walking-out dress, you CAN wear a long sleeve shirt with nothing more than a sweater or canex jacket over-top and "walk out" wearing that.
Further, I feel like we've skipped a step in terms of environmentally (temperature) appropriate orders of dress. In hot weather, we wear the short sleeve. In cold weather, we wear long-sleeve with sweater. Well, what about "cool" weather? Well, in those cases you wear the long sleeve without the sweater, but there are restrictions on that (i.e. it can't be walking out dress).
I have worked in several offices, and during the winter months, everyone is wearing shirt and tie sans sweater, because it's generally too cool to wear a short sleeve (not to mention it's not permitted), and always warm enough that with proper heating you don't need a sweater.
I just wish in these "office" situations we had a name tag on our long sleeve. It helps when you are at a big unit (or new unit) and have no idea what peoples names are.
As an aside, in purely office units (HQs, some schools, etc), I like the look of shirt and tie better than short sleeve. Short sleeve with all the bling makes it look like were all getting ready for a parade. IMO.