- Being cut out for software engineering activities; vs software engineering career/success, may be different skills and concepts. You could be good at development, system administration database administration; without necessarily being good at succeeding in any particular type of company culture or organization, applying those skills. Which one is your question: can a person be "not cut out for software engineering", or can a person be "not cut out for success at particular type of company as a software engineer"? [I would give the answer for both a "probably, in principle, but less often than assumed].
- You mention some of your perceived history of effort, success, and lack of success. What about more personal stuff - do you ENJOY the work? Are you attracted to software engineering (however you see it - development, sysadmin, etc)? Would you dabble with it even if you got a job in an unrelated field?
- Do you have a specific filter you might or might not be aware of? Are you seeking specific types of jobs in specific types of companies under specific constraints?
- Do you have friends you trust in similar professions, or with similar interests? What do they say?
- How about colleagues, classmates, profs?
- Number of failures at obtaining jobs is a metric but not a predictive one without context. Skill at interviews is not the same as skill at software engineering is not the same as skill at organizational success.
- Similarly, you may have _perceived_ to be working harder at college; you may have _actually_ been working harder, due to your higher standards; you may have been working harder but _not_ receiving the same results as others - without full understanding I would not automatically put full weight in your perception of relative work.
- Top Companies and Top Projects may not have one-to-one ration. Why do you think you want/need to work for those particular companies? Are you interested in prestige of the name? If not, what is your true interest - type of work? Team culture? Accomplishment? Paycheque? Write a list of your actual priorities, be brutally honest with yourself, and see how they match with those "top-tier companies".
- How would you perceive your skillset at large? Your communication skills, people skills, friendliness, dependability and reliability, loyalty? Personally, I look for a reliable willing learner on my teams more than somebody who can solve puzzles but will cause havoc - different companies have different fashions however.
Either way, best of luck :)