When people say "biking on the sidewalk", I don't think most people are talking about the last 10 metres from the parking to the dedicated bike path. They usually mean riding hundreds of metres up into the kilometres along footpaths.

The necessary approach to fix the issue is different in both cases. In the case I think most people mean, the fix is...install proper dedicated bike paths.

In the case you describe, the answer is that kerb cuts should be fairly frequent to minimise the distance needed, and to mark the space around popular bike parking areas as a shared space, probably with some different colour tiling and tactile ground to make it clear to everyone (pedestrian and cyclist alike) that the space is shared and they should be careful.