Word of advice for responding to OPs: read the post before telling OP they're doing it wrong.

OP: "asking for a very detailed quote, portfolio examples and an estimate..."

You: "when you send a resume out and don't get a reply"

These are not the same. A response to an RFP is not a "cold resume". It's not an application. It's custom, one off, strategic work at the requester's request, and deserves at least an acknowledgement.

I'm not sure you read the OP? He's talking about companies contacting HIM to ask his rates and then not responding once he offers it? Hence the use of the term 'spam'?

People who are too busy to handle the hiring process should NOT post job ads. Period. That's what OP is talking about -- disrespect. If you place an ad, with very detailed requirements, and are not prepared to handle the process of application intake and processing, then you are wasting everyone's time and showing blatant disrespect to candidates.