Note that an engineer at a startup doesn't necessarily need to focus on anything other than engineering. If your startup has 2-3 people, then sure, everyone's gotta wear multiple hats; in a startup with 10-20 people, specialization makes sense, and probably wouldn't be that different from a big company.
(One big difference, however, is that even if you're doing only engineering work, a big company will probably give you more time to think long-term; at a (competently-run) startup, you're more likely to be focused on short-term, tactical, quick-and-dirty work.)
(One big difference, however, is that even if you're doing only engineering work, a big company will probably give you more time to think long-term; at a (competently-run) startup, you're more likely to be focused on short-term, tactical, quick-and-dirty work.)