There are certainly startups hoping to become redwoods, but there seem to be many with goals or target markets that would likely limit them to shrubs at best. Of course, there is also a large class of "startups" that are a lot more like Christmas tree farm seedlings.
The author's point is that both IBM and the local bakery are built to last, patiently building value over time.
Startups are too often get-rich-quick schemes whose founders want to work hard for 3 years, then cash out and spend the rest of their time on 'speeches and beaches'.
IBM wasn't "built to last." It was a rollup of a bunch of cash register companies, handed to Watson to run by the financier who bought them.
The truth is that in reality there's usually less planning than there later seems to have been. Things that turn out big were often small and tentative initially.