For raster images, you can already do this within Illustrator.
1-Copy the vectors of the mask (JUST the vector, not the image contained inside!)
2-Deselect all and click to selected the mask + masked image set
3-Set the mixing option in the Transparency palette to Multiply
4-Paste the mask vector in back (Ctrl + B) and paint it white
5-Shift+click to selected also the mask + masked image set again.
6-Group (Shift + G)
7-From the Object menu, select "Flatten transparency", setting quality adequately

(This may create segmented images, which you may optionally just rasterize again as a whole single image.)

This will create a standalone raster image in the size of the mask. However, this process is not perfect, and if you need precise pixels around the borders of the image, you might still need a mask to create crisp edges.

When one creates a clipping mask using two or more objects, it should be a simple right click option to "apply the mask" and flatten all related objects into a new vector. Currently you can do this by going to layers and selecting the "Clipping Path" layer of choice and then using the "Crop" Pathfinder function to achieve this, however, this method is extremely non-obvious. I don't propose removing the pathfinder function as a way to apply clipping masks, but simply to add a more obvious way to do so.

Yes!!

A destructive clipping mask would be nice. I have to save as svg for the laser printer, and the svg shows the clipped area!

Please let the Expand function work for Clipping Groups as well, to get rid of the Clipping Mask while keeping the intersected objects.

I have wanted this feature for years, would be very handy and time saving.

Jotham, not exactly. Trim also destroys art in the middle of the mask, which should here stayed as it is.

Pathfinder - trim does exactly what you are asking if it's vector elements. Astute graphics made a plugin that does it for raster images, but it would be nice if Adobe implemented it as well.

Very interested in being able to crop or trim elements outside of a mask or clipping path and delete them as an option!!