This is a huge pet peeve for me.
Anyone who spends the money on decent speakers should be using the good speakers all the time.
Surround sound is obvious for movies, but you don't just buy 'different' speakers, you are supposed to have bought speakers which are significantly better than those inside your television. This means that for basic viewing, such as the news or a game show, you are going to get much more accurate sound. At a lower volume, you should get more intelligible listening which won't cause as much ear strain when listening to the dialog.
I almost never see A/V receivers have issues, and typically, a good universal remote makes it one-touch easy to use the full HT system as it does for just using the cheap TV speakers.
Obviously, I use my good speakers all the time, but I really do balk at those who spend the money and then don't use them. There has NEVER been a good reason which I've heard not to use them.
The car reference is a good concept, but in reality, you aren't 'driving' your A/V system, you are listening. Whether it's a HD concert disc, or the local news, you are using the same display, and your same ears - so, why not make it as pleasurable as possible regardless? More like teleporting to the local store, or the one across town. It's just as easy and beneficial to teleport to both locations. Sure, you could walk to the closer one, but it would just be stupid to do so.