Confusion arises because who gets to say that's the metric that counts? What are your criteria for a business to be considered alive and healthy? Why are those your criteria?
Growth is not inherently positive, it depends on context. For example, if I tell you my cancer has grown 500% this year, it wouldn't be good news. And before you say this is a stretched analogy, it's not necessarily positive in tech either - if you're growing while bleeding money, all you're doing is bleeding more money. So how do you reach your conclusions?
Confusion arises for a lot of reasons, but cancer definitely isn't a useful analogy to discuss a blog post that starts "Most high-growth businesses..."
It's definitely the metric that counts for the kinds of businesses Andreessen Horowitz cares about.
Microsoft and Yahoo are particularly confusing examples, because they are both very large companies who enjoyed a lot of first mover advantage, but were started almost 20 years apart. And then ended up as very direct competition, before settling down as symbiotic partners. If you really want to use an example from biology, you should look at gut bacteria.
Microsoft's corpse has similarly been squirting billions of dollars of profit through its several layers of tombstones for decades now.