[jacknews]

These were because technology changed, not because of better competitors doing the same thinig

[WalterBright]

They did the same thing as far as the customer was concerned, only better, thereby offering a better deal to customers, who switched.

[jacknews]

but it negates your point that lazy incumbents will get disrupted by nimbler competitors.

That mostly happens when the 'nimbler competitors' are in fact armed with a completely new technology, business model, etc.

ie, innovation is the key to change, not just decay of the old making way for more of the same, but more vigorous.