Welcome to the forum.
3. The late ones,

the ones who hear it through the mainstream media. When this happens it is usually not ever worth it anymore not saying you wont make money but you will work 4-5 times harder than the 2nd person leaving you earning pennies (Saturated)
It's never too late to get bitcoin, you can always get a job and negotiate to get paid in bitcoin, or just buy as much bitcoin as the people who came here ~3 years before you, with cash. It all comes down to the fact that currency or any kind of money, not just cryptocurrencies, cannot be collected for free. There are no places that reward you with lots of free USD for doing easy work. You must work to get it, and by that I mean skilled work that requires high talent, since there are fewer people around who have such skills.
Learn a skill, and use it to earn bitcoin.