I would say odds low;
Pros:
- Great history and serves to attract talent
- Team have a great history of spotting and brining forward start-ups with potential which would imply some future odds.
- Team in better position (knowledge/connections) to increase companies changes of success.
- US dominated which has best history of unicorns to date.
- Scale increasing helps increase possibilities.
Cons:
- Quora says about ~2m tech start-ups a year. Even if YC has huge likelihood of success over average, its still a drop in the bucket of possible.
- While they are global, unicorns will increasingly come from non-US where they have less coverage
- YC is growing in scale and I assume that will come at some cost in how much they can add value.
- Apple level company is such a rare event even with successful startups. I'll define 'Apple company' as $1 trillion+ - that one of 5 companies in the world today. So even if you build a $500bn company, its far from 'Apple'
- I think Internet/IT revolution is getting hard to succeed at that level form a start-up from a start-up. There so much more established business to fill/buy/build out products than there was 20+ years ago vs 2 guys and a dream.
...but really who knows, so many variables vs my 5 min pondering. I feel the odds are slim.