Demand for commission only marketing agency?

I currently run a commission only marketing agency, but I'm struggling to find clients. Instead of a monthly retainer fee we only share the revenue that we bring in.

I thought this would be a good business model but i think clients are used to the monthly flat fee as opposed to profit sharing.

We specialize in high-ticket ($800+) products. Usually custom made or tailored services.

Is there anyone else using this model for their agency? What are your thoughts? Any advice on how to succeed with this model? any niches i should target? or should I just pivot away from performance based?

lmk in the comments or feel free to pm...