Every store is different.
But honestly, a ticket counter would take twice as long! An elderly woman doesn't want to haul her iMac into the store to take a ticket and wait for an hour. She want's to make an appointment for 3PM and carry it in for direct service. For simple questions an appointment is not needed, such as small iOS questions or a system navigating problem.
Also, the sales team is not the "Genius Bar" Apple can not afford to have 50+ Dedicated support and "Geniuses." The sales team is not always crazed Mac users, as this is "just another sales job
" to a lot of them. So waltzing up to these sales persons does not always mean guaranteed answers, because that is not their first job-selling is. They are only trained in the basics of the products, that would be the roughly the most they can help you with. Anything bigger and make an appointment.
You can't always walk into a BMW dealer and speak directly to a Tech in the garage, and most likely the salesman can't answer your question.
Being this big and dealing with hundreds of people per day, online appointments are a necessity.
Plus like Tim Cook would ever listen to me