I get your argument and I appreciate it. But the nature of those low hanging fruit are more complicated today. For example, you can't just recreate Twitter, Facebook, Reddit today in your home with a couple of friends with no solid experience. You similarly can't start most successful SaaS ideas that were started in 2010-2014. Most successful YouTubers started their channels around 2008-2011. This was a time when you could make a very successful venture relying on the viral marketing by social media and Google search. Nowadays, this is over. You can go and try this same hippie way for starting a small business today but your chances of success are 1000x lower. The internet is much bigger, and it's much more centralized and concentrated and the competition is much more harsher.
Snapchat was founded in 2011 when people thought there couldn't be any other successful social media company. On the other hand, Salesforce, an epitome of SAAS, was founded in 1999. I believe there are always business opportunities and I'd argue there are more opportunities today because the space is more complicated and the cost of starting a company is much lower than before.
I don't necessarily disagree with your argument, but Snapchat might not be the best example. Snap has never posted a profit and their stock, even after a rise of almost 275% this calendar year, is still 42% below its IPO price.
