It's the world that has changed. Launching into a relatively open world wide web is fundamentally different to breaking into the consolidated platforms of today. Startup culture was at its peak in the PG days today it's closer to a nadir.
Yes, totally. I became interested in startups in 2009. I was a CS major and there was a tiny group of other students who shared my interests - we had a weekly "internet entrepreneur society" meetup where we'd discuss Paul Graham, Eric Ries, "Getting Real" (37Signal's book), and so on, along with the various projects we were working on and ideas we had.
By the time I graduated in 2012 the field was already starting to change. In the first two years out of university I worked with 3 different co-founders on various ideas, none of which went anywhere (frustratingly). Two of those co-founders had no genuine interest in technology or innovation -- I believe that they only became interested in startups after they became the hot thing to do. They wanted prestige and they wanted to raise funding for the sake of it. They weren't excited by the potential of the new platforms that had just appeared.
(After that I ended up working for a medium-sized tech startup for a while, got disillusioned and burnt out, took some time off, and then spent the last 3 years building myself back up. I still want to take a real shot at starting a startup, but the industry has changed so much now. The fun and excitement has gone).
I think there were several factors that changed startup culture:
1. The technology of the web matured. We are now in the Gartner cycle "plateau of productivity". Once upon a time you could upload some PHP scripts and a little bit of AJAX and have an interactive app that was admittedly crappy, but also genuinely novel and interesting. Now you need to know a complex backend framework, the modern JS ecosystem, automation/build tools, etc, just to compete. That's fine for a 10-man dev team, for 2 founders out of college it's a daunting amount of work.
2. Startups became a much more popular and prestigious career path. "The Social Network" movie (2011) made startups much more glamorous. Tons of articles were boosting "disruptive innovation". By the time I graduated, suddenly all the kids who'd been polishing their IB/consulting applications decided they wanted to be entrepreneurs, maybe after 2 years at Goldman/Bain/etc. Some of these guys were genuinely talented and cool. Many were arrogant and douchey, had a shallow understanding of tech, and treated their technical cofounders as code monkeys (yes, I had a few bad experiences).
Many interesting startup ideas (Apple, Microsoft, Facebook, Google) came from young technologists working on ideas they thought were cool, yet were niche and weird at the time. Once the IB kids started entering tech en masse the culture shifted. (Granted the Winklevoss twins tried to recruit Zuckerberg back in 2004. So this is not completely new. But I think the techie/suit ratio changed dramatically in the early 10s).
3. Lots of cheap capital. This meant more ideas funded, ideas that got funded raising more money, and more market saturation in web, mobile, everywhere. In some ways this helped entrepreneurs, but it also made fundraising more necessary.
4. A controversial one: all the "sexism in tech" controversies that kicked off a few years ago. I paid close attention and I remember that this exploded in 2013. You had things like a Github founder being ousted (along with Github apologising for their "meritocracy" carpet), people being fired for tweets, etc. Sexism is wrong and there were probably many invisible barriers to female founders. However the big social justice activists (Shanley Kane, etc) were not concerned with technology, they were motivated by ideology, and they created a very hostile atmosphere. Make an edgy joke on a blog post intended for about 100 friends to read? Suddenly 50,000 people on Twitter have read it and are calling for your head. PG made a poorly-worded comment during a long interview -- suddenly every media outlet quotes it out of context, takes it as proof of his sexism, and it becomes untenable for him to remain in charge of YC. (I know this wasn't the only reason he stepped down, but it was a factor).
5. Regulation. GDPR is the biggest one, though there are others. It is not a startup killer, startups can still operate, but it makes it much harder. The idea of putting a prototype online, getting some early users, and rapidly iterating based on feedback is now much more dangerous. You need to invest heavily upfront to become compliant (even then your legal status will be unclear), and if you pivot, or make drastic changes, you bear the risk of becoming non-compliant. The EU legislators assume that everyone is a big company with a stable business model, not a 3-man team experimenting with various ideas. These regulatory changes went hand-in-hand with increasing political hostility to tech entrepreneurs. Say you manage to succeed despite all the obstacles put in the place of tech entrepreneurs in 2018, and become the next Mark Zuckerberg -- you can expect to be treated like the current Mark Zuckerberg, that is, have everyone hate you and try to get you fired.