First, because I think you're factually mistaken - for a lot of people, a big name on your resume is a huge, positive flag.
Second, because there are other effects of working at a large company which you're not considering. Most importantly - they're large! That means you're going to interact with a huge amount of people. In 3 years at a BigCo, you'll likely have contacts not only in various departments, but probably in several other companies as well, both because of work with outside companies, and because of interacting with employees who left.
Not to mention, you can learn a lot about the industry that you might not necessarily be exposed to while at a small startup - via interactions with those outside companies (customers, partners, etc). You can also work on seriously big things, which you won't be working on at a startup, for example.
None of this is to say that working at a BigCo is the right move. I actually tend to think the opposite, depending on various factors. But it's definitely not an all-downsides proposition.
First, because I think you're factually mistaken - for a lot of people, a big name on your resume is a huge, positive flag.
Second, because there are other effects of working at a large company which you're not considering. Most importantly - they're large! That means you're going to interact with a huge amount of people. In 3 years at a BigCo, you'll likely have contacts not only in various departments, but probably in several other companies as well, both because of work with outside companies, and because of interacting with employees who left.
Not to mention, you can learn a lot about the industry that you might not necessarily be exposed to while at a small startup - via interactions with those outside companies (customers, partners, etc). You can also work on seriously big things, which you won't be working on at a startup, for example.
None of this is to say that working at a BigCo is the right move. I actually tend to think the opposite, depending on various factors. But it's definitely not an all-downsides proposition.