Okay, maybe it will max out somewhat above 15%. After all, Oulu, Finland, with similar infrastructure, is at 22%. However, in 1962, before they put this infrastructure in, they had a 44% modal share for bikes. I'm just pointing out that if you restrict any mode to a very confined space you will at some point bump up against those space constraints.

That's neither positive nor negative; it's a very real factor to consider when evaluating proposed or implemented infrastructure.