Finance of Circular Economy and SMEs

I am looking into Circular Economy and its relation to finance. What would you say are the biggest obstacle for small medium enterprises (SME) in terms of finance when they would like to participate in activities of CE?

A lot of asset management based models e.g. product as a service requires significant capital requirements. Returns are slow based on rent income rather than product sales so requires financiers to be on board with long term benefits or lower RoI in the nearer term.