Podcaster/bloggers are less interested in commission than maintaining their relationship with their audience.

I've found that approaching bloggers with an opportunity for early access, prizes for giveaways, free product to review is far more effective as an icebreaker.

Once they have a review or podcast then you can have a conversation on how they can monetize it via affiliate links.

Additionally email may be the wrong venue to approach them, your email could be getting lost in the noise if they are getting a ton of unsolicited emails daily.

If the opportunity is big enough send a small gift to get their attention. Stand apart from the crowd.

Hope this helps.

Mick