As a corporate pilot, you'll be at a noticeable disadvantage in building experience relevant to the majors (it's not 121, and there's usually less of it). You'll also be less competitive than a similarly-experienced regional CA, since he's a known quantity in the 121 context.

Check out the corporate and fractional forums to see what's going on there right now.

All that said, you'll get there eventually if you avoid fly-by-night corporate operations which will get you violated and/or poison your reference well when you pizz them off by quitting for a better job.