Well..product cannibalization is different than a professional moving up the value-chain.
A professional is trading hours for dollars, the only way to increase their income is to either arbitrage cheap tasks (i.e. hire low-paid professionals and bill them out at a higher rate), increase the amount of hours they bill, increase their hourly rate.
The best paid in an industry tend to have the highest hourly rate - not necessarily the most amount of hours worked.
So, it would seem to me, that all professionals should be looking to move up the value-chain.
Clerky forces lawyers to make a choice. They can either fight for the 'automatable stuff' or they can move up the value-chain.
If you're not already familiar with him, there's a great professor at Harvard Law School, Ashish Nanda, who writes about exactly that - the choices service providers have to make as to where on the value chain they sit:
If the old guard aren't the ones destroying their business, then they should be petrified of anyone who gains a beachhead.