The "buy-it-for-life" brands ran into this problem because once you sell someone the classic product, they aren't going to sell another one unless it's to another (new) customer or purchased as a gift for someone by their existing loyal customer. So then they start entering into new product areas and eventually end up compromising quality.
As other have mentioned, this is becoming particularly annoying with home appliances and cars. "They don't make them like they used to" are true words.