Do you think you had to go through those first few small wins in order to finally take a swing at a homerun? What changed when you did treehouse vs those other smaller businesses? Was it the fact that you didn't need to worry about money in the short-term anymore (because of those small exits), or something else?
I'm not certain how valid it is as advice, it feels like something that might suit some entrepreneurs but not others.
In startup culture successful founders are portrayed and stereotyped as being in their early 20s, college dropouts, first time founders, etc. but when you dig deeper you find that this is far from true.
One age, the HBR recently analyzed data from Crunchbase and other sources and found that the average entrepreneur funding age is 31[0]. This means most have around 10 years of industry experience before getting funded, on average. YC would skew a lot younger (it probably shouldn't, but it does).
Second is the "first time" myth. If you look at successful entrepreneurs, even those who appear to be hits with their first company - you'll find that they all have at least some experience with delivering a product that people used before their big hit. It is a big leap to go from just having ideas and reading articles to actually building a product to completion, find even a hundred people to use it and then running through a few user feedback based iterations.
The same startup lore that mythologizes young first time founders usually also always mention a previous product from the founders that had some success (blue boxes, facesmash, altair basic, etc.)
The data shows that entrepreneurs have product or industry experience and aren't in their early 20s. You can fill that time in with your own products and aim to work on the basics such as getting a product built and launched, listening to users, etc. If you can't do it at a 100 user, $10k scale the chances of you being able to do it at a million/million scale are likely slim.
There is also no reason why the 100/$10k startup can't scale up to a million/million startup - you just need to put a price on the product or your time from day 1 (product scales better) and grow steadily. But it is also good to know when an idea has reached its limits and you should exit, investing your time in taking the next idea to x.
For some entrepreneurs they'll be comfortable spending that pre-time before the "big swing" idea in other startups (and perhaps failing) or small-scale products, or alternatively 4-5 years in industry.
[0] http://blogs.hbr.org/2014/04/how-old-are-silicon-valleys-top...