Can modifiers be computed and applied from the command line? For heavy modifiers, the time it  takes to compute can range between a few seconds to half an hour or longer.

Can modifiers be added, computed, and applied from the command line with some sort of indicator of progress?

Running from the command line would be useful for running blender GUI-less without a WM to save memory.
It would also be ideal to have some idea of how far along the modifier is.
You'd have to use bpy.ops.object.modifier_apply, e.g.

import bpy

for obj in bpy.context.scene.objects:
    bpy.context.scene.objects.active = obj
    count = 1
    length = len(obj.modifiers)
    while obj.modifiers:
        name = obj.modifiers[0].name
        print("%s: Applying %s (%d/%d)" % (obj, name, count, length))
        bpy.ops.object.modifier_apply(modifier=name)
        count += 1
print("All done.")


For info on how to to run the above, see here.