Ahh. That makes sense.
I was just saying on someone else's thread...when I lived in eastern Ontario I collected quite a few really nice classic cotton long sleeve shirts.
1. It's a no brainer style for me in terms of fit and flattery.
2. Classic styles -- they never really date!
3. My colours often available!
4. I genuinely LIKE them!!
And then....weirdly...I rarely wore them. It made me feel SO guilty. All that $$$....for what?
Luckily, I kept them. Lo and behold. Move me to a slightly more temperate climate and these shirts earn their keep in the biggest possible way. I wear them now from April through June (and sometimes, esp. cotton gauze or linen ones in July/ August) and then again from September-October, not just as a layering piece but as either a layering piece or a piece on its own, and they are perfect!
All to say, I get where you are coming from. Smart idea to layer with an undershirt -- you will get lots more wear from the shirt.
Angie suggested to me that for winter I look at flannel shirts (which I know you have also done.) I really enjoy my winter shirts and get good mileage from them. But there is something about a crisp shirt that is infinitely more elegant. This one being a case in point.