Why Don't Companies Offer Internships for Adults?

Dear Experts, Why don’t companies offer internships to adults who are looking to change jobs , industries, or just learn something new? It seems with so many people out of work, they could benefit from people with real world experience. I know I would love (and have applied for) internships that focus on social media and public relations. Our Twitter Advice Project (T.A.P.) is no longer an active campaign. To find an answer to the above question, please use the "Search" box in the right-hand column of this website.