Is McIntosh a stepping stone into HI/FI?

If its just a stepping stone, its a pretty expensive one.

Mac gear is a reasonable choice for many hifi systems. Looks nice too! Nothing wrong with that.

I'll go out on a limb and say mac gear is generally not the best bang for the buck sound wise, especially in the internet age, but most gear is not that.

If you look through the for sale ads here on the 'Gon, you'll quickly discover that ALL brands are being offered for sale, so I've come to the conclusion that most folks are never happy with what they own, and are constantly searching for something different. Whose to say that the other brands you mention are the right sound? Read the audio mags, and you'll feel like you need to constantly upgrade to have better sound. Once on this merry-go-round, it never ends. Personally, I like the Mac "sound", and whose to say that it isn't right? Although I can't answer your question about coming back, because I've never left, I find the Mac sound quite pleasing. And after all, that's what really matters, not what brand you own.

I like the Mac sound for me nothing beat the Mac

If you've got MAC you are there!