You may not know it but the company you are applying to is an affiliate of the company you are already working for.
I didn't realize this until months after being into the field of academic writing. I tried applying for numerous sites and got turned down because I was working for the affiliate company. Then again, it wouldn't make sense for a writer to be part of the other company, considering the fact that they do in fact consolidate the orders into one pool. At the very end, the writer should find a way to be able to expand their writing portfolio to be able to create a full-time career out of this field.
Writers also shouldn't focus too much on how many "companies" they are working for. While diversifying your career is different, to be able to retain customers in specific companies and platforms is what is more important. To make it sustainable, don't look for companies that are
just easy to get into. Instead, look for companies that are actually communicative, friendly, and fair to their writers. Whatever the definition of the execution of these three are would be largely just dependent on the writer's perception himself.