Many start-ups fail. Even profitable start-ups can fail. Why? One reason is because they might have a cash flow problem. They could sell a wildly profitable contract to a customer due in one year, but if they have no money today, then they are in real trouble. What does this have to do with recruiting? Well, recruiting has the same problem. Let's say you apply to 10 companies. Before getting any interviews, immediately 4 firms reject you. 6 companies left. Then, after your 6 first round interviews (a great hit rate by any metric), 2 companies reject you. 4 companies left.
Then, after your final round interviews, 3 companies reject you. 1 company left.
Then, after months and months of effort, you finally get your offer. See, you could be a wildly smart, qualified candidate, but still get demoralized by the recruitment process because of its timing problem. Imagine if you got your one offer up front, and 9 rejections later? That'd be amazing! There'd be no stress. But, unfortunately, it doesn't work that way. Don't be a failed start-up. Small businesses need sufficient cash to survive, but people are stronger. We can take the rejections, improve, and try again. We can have a cash flow problem for months or years, but still stay in business.
My takeaway from all this? Don't give up. You are wildly smart and qualified; the recruitment process just has a cash flow problem.