Let's say an agent (or an editor) requests changes. The changes are made. The agent (or editor) then passes. Should the author continue submitting the original book or the latest version?(I'm thinking conceptual changes that brought the book closer to the agent's/editor's tastes and not fixes.)
Did it make the book better? If an editor requests revisions that I think make the book better, I strongly encourage my client to make them even if I'm not so sure an offer will follow. I say to the client "we'll have a better book to shop even if we don't sell it here".
If you think the changes are stupid, wait a month, think again, and if you still think they are stupid, don't keep them.
You shop the best book you can.