Almost no one wins submitting proposals out of the blue, certainly the case with unsolicited proposals but also with responses to formal RFPs. Firing in a proposal with no agency contact, no familiarity ("customer intimacy"), no shaping, no premarketing, no office calls, no digging to understand their real pain points is even worse than a cold call because, as you noted, it is horrendously more expensive and painful to prepare a large proposal.