To start off, I'd say that the mobile screen size is way more heterogeneous than the computer one. In mobile devices we have landscape and portrait mode, whilst in computers it's pretty odd to have a portrait screen.
Also the size of the screen so small, accounts for significant changes in screen real state when it changes from one size to the other even by a small difference, complicating things.
Another thing that it's heterogeneous is the pointing device, sometimes it's a joystick, a roller ball, the finger, which makes it difficult to forecast every single type of user, as opposed to the computer, where pretty much everyone has a mouse and a well sized keyboard.
I think this might be one of the main reasons for mobile web pages, to be limited versions of their desktop ones, and this is why, many applications offer means to the desktop site from within the mobile one.
In the mobile landscape, some applications offer small level depth and a drawer for options.
Flattening the structure of the site, reduces the need for breadcrumbs but also limits the functionality and distorts the Information Architecture for a desktop site. This is called Content Prioritization.
For example (This is Architecture not Breadcrumbs, and it's only an example to make my point. The structure of the Article in the content repository remains the same regardless of the interface, mobile or desktop, where it's presented):
From my perspective, this is expected to some extent on the user side, as the users usually don't need to perform difficult tasks on their phones as the device is also limited on size to operate it comfortably.
Have a look at this website: