Never say never. Unyieldingly binding your company to its most-enthusiastic customers at a single point in time ossifies it. Kodak and Blackberry, it could be argued, failed by refusing to bail on sinking ships.
I think you're misunderstanding their point. The gp was saying don't ever attack your most enthusiastic customers, parent was suggesting there is equal potential for harm in refusing to detach from your enthusiasts and citing Kodak as an example. Sometimes your most enthusiastic customers are also out of touch with how the rest of the industry is heading - it's easy to get complacent and fall from the top.
Never ever attack your most enthusiastic customers.