As a person that currently maintains separate versions for desktop and mobile - it is not shameful. It is just good sense.
You are still constrained with a lot of low power devices on the mobile side and old versions of IE on the desktop side. So it is big PITA to reconcile all of this.
In 5 year they will converge but right now it is too early.
The needs of both are the same: simple, readable design. Every time I see a site with these two versions I've found that I preferred one to the other, on both devices - either the desktop version's better even on mobile, or (usually) the mobile version's better even on desktop.
You are still constrained with a lot of low power devices on the mobile side and old versions of IE on the desktop side. So it is big PITA to reconcile all of this.
In 5 year they will converge but right now it is too early.