(a) one person being able to do the job of the entire YC team.
(b) that person having equivalent relationships with additional capital.
(c) one might make the case that the relationships to capital must be better because ventures are likely to be located further from conventional sources of capital.
50% equity is a lot to give up for two months of effort unless the other co-founder is only expected to put in the initial two months. And if that's the case, why bother?
The comparison is the basis for estimating a rate of success relative to resources available to a company entering the OP's program.
If the OP is investing in only one or two companies at a time, then it is practical for him to participate in YC in his role as cofounder. If it's 25 companies, then it is more difficult.
The entire YC team can advise ~66 startups and they have ~14 people which suggests a person can advise 4-5 startups at a YC-level. It's not quite equivalent since YC has the benefit of multiple perspectives though at the cost of increased coordination.
The truth of b & c are completely dependent on who hmexx is.
YC also has Yuri Milner, Andreessen Horowitz, General Catalyst, and Maverick Capital working with any company which takes a convertible note.
Furthermore, those companies taking the note have a much longer runway than hmexx will provide and will be plugged in to a network of later stage investors.
Finally, each YC company has access to the other companies in its class and the YC alumni...and lots of other things in the valley.
It's logically possible hmexx could approach a similar level of success but it looks unlikely.
YC has those things now. At the beginning it didn't have any of these things, and a few really successful startups emerged from those early days even with YC not having guaranteed follow on funding, not having a large network of alumni and not having the reputation.
(a) one person being able to do the job of the entire YC team.
(b) that person having equivalent relationships with additional capital.
(c) one might make the case that the relationships to capital must be better because ventures are likely to be located further from conventional sources of capital.
50% equity is a lot to give up for two months of effort unless the other co-founder is only expected to put in the initial two months. And if that's the case, why bother?