What jrockway describes is a common pattern; it's not necessarily the end of the company IME, but it's the end of the spirit of that company, whatever made them

What jrockway describes is a common pattern; it's not necessarily the end of the company IME, but it's the end of the spirit of that company, whatever made them great is gone, they're riding on their laurels (relying on past 'wins'). Cadbury is a brand like this, as soon as they started smoothing corners on their chocolate bars to save a few percent volume and making the chocolate waxy they died. I expect under Kraft/Mondelez the brand is making more money than ever though. I suspect there's a transition from R&D/development spending to marketing spending that marks the change.