So your saying people who drive cars should walk further to get to Sutter Street than people who ride bikes????? And as far as shopping goes, I've seen few bicyclists carrying significant purchases from local businesses anywhere in Folsom......unless you count the few 3-wheel trikes with baskets.
Short answer: yes. A good rule of thumb is that the bike parking at any business should be at least as close as the closest non-ADA parking space. The "best practice" for locating bike parking (as described in the Association of Pedestrian and Bicycle Professionals Guide to Bike Parking) is that it be between 50' and 120' of the main entrance. Why? Primarily because if it is not, it won't get used. If it is off in a corner somewhere, bicyclists are likely not to even find it. If they don't find it, they will park their bikes wherever they can find to do so. So, if merchants don't want to be "plagued" by bikes parked randomly along the street, there needs to be convenient bike parking. More importantly, it needs to be in a high-traffic and/or highly visible location to minimize the chance of theft or vandalism (all but the very best locks are merely a speed bump for a determined thief). In the historic district, because of the proximity to the American River Parkway Bike Path, you have the added complication that most cyclists will not be carrying a lock. So, if they can't park their bike somewhere where they can keep an eye on it, they simply won't stop and spend money (that's a major reason -- in addition to good food -- why Karen's and the Sutter Street Grille are so popular with cyclists). Most Sutter Street shops are small enough that one can park a bike out front and keep an eye on it from inside the store.
As for the lack of observed bike shoppers, Folsom's bike scene is certainly focused on recreation at this point. Yes, Folsom is in the heart of suburbia, where people tend to think of bicycling purely as a recreational activity; certainly our elected leaders do. But part of the reason is that the infrastructure is missing. For more on this, see my previous posts on shopping by bike. The fact is that most shopping trips do not involve large quantities of goods or a great distance. They are perfect trips to be done by bike. If you can go through the 10 items or less line at the grocery store, you can carry that home on a bike.
More to the point, I don't understand why people are so hostile to the idea of providing basic amenities for cyclists (they are, after all, required by the city's zoning code). Bike racks are cheap: a rack to park 2 bikes costs a couple hundred dollars installed, compared to about $8000 for a single automobile parking spot. Same rack takes up 4" x 2.5' when empty, and about 3'x6' when full, compared to a 10'x20' auto parking spot (not including required access aisles which nearly double the total space). Every bike parked in a rack frees up a parking spot for someone else in a car. It's a really efficient way to get more customers into the district. Isn't that the goal? Even if they only patronize restaurants, cyclists add significantly to the economic vitality of the district. I suspect that if you looked at sales taxes in the district, the majority would be from the eating/drinking establishments. they are a very substantial portion of the business mix, and I suspect account for the majority of paying customers.