Of course the computer repair services use the same software and do the same things. Just like car mechanics, appliance repairmen and any other fixit service. It's even been rumored that most carpenters use hammers and nails! ;-)
One difference between services is that the better ones know how to fix obscure problems that their "software kits" can't. And the better services might actually pay for software that does the job better than freeware. This costs $$$. Do you want to fork over $200 for the best hard drive file recovery software app (which still requires in-depth knowledge of how files are stored) in the off chance your drive fails and you never did backups? Far cheaper to just do backups!
You can learn to do what the services do without having someone show you. Every technique and answer is out there on the web. But if you can't self-teach from this, then you're not the type who can do this kind of work.
Many services of course don't want to teach you how to do the repairs; that means less work for them in the future. That's called business. Though, some forward-thinking services might actually teach you the basics for goodwill and referrals.