In the offline world - most of the largest businesses have been traditionally started by Solo-Founder with some support from friends and family. (Think Andrew Carnegie, Honda, Colonel Sanders and many more)

There is a discrimination in the valley against solo founders because INVESTORS feel much safer investing in multiple people vs backing a single individual!

What Mark is suggesting in this article is actually a very intelligent mid-way path .. Start solo, build your MVP, Get some traction , some angel funding , some customers and then hire a Co-Founder or better still employees with generous stock options.