Take Colosuss who in the reg. series was a 70 ton and his power increased up to 100 tons. I agree that learning control can be the cause of generating more power, but it is still a power increase. Mabey i mispoke but what i mean is that these mutants, like brotherhood with blob becoming freedom force, gain more power as they age, the same as we get stronger as we grow older.
Now as far as the Blob is concerned, i was thinking that this might be the way his power works. One his skin just takes a hit, and two he generates a field of 5 feet that won't allow him to be moved. His generation of that field may work like magnetos. He not only self generates a field, but when he is attacked the attackers strength generates an equal amount of the same field, rendering moving the blob impossible. Rip up the ground or on occassion like someone said the Hulk once did, yes, but I doubt every time that it would be as succussfull.
Just like Juggy gets stoped, Hulk gets trounced the Blob may move.