I have the same memories. Obviously we can never know for certain but if notch had decided not to hire anyone and continued to work on the game himself, I’m very confident it would have eventually made a billion. The core game hasn’t changed since 2010, and it was already absolutely captivating in those early days.

Found this thread from around that time, it's fun to read now:

https://news.ycombinator.com/item?id=1740289