The efforts to get business to let people carry in them that have been successful seem to be those efforts that don't try to punish businesses for not complying, but instead are those efforts that attempt to persuade in a logical manner the reasons why it is in fact beneficial for a business to allow law abiding citizens to carry.
And we've had especially good luck with rewarding and reinforcing good behavior -- witness the Starbucks "buycott" where gun owners dedicated a day to buying something from that company.
Probably happens that way because the business owner doesn't see the dollars that would have
come into the business. They only see the dollars that actually do come in.