The difference is that in the exploitative AAA shop, the company pays salary and benefits. In the exploitative indie shop, "something" will happen that means you are also unpaid and have no recourse because the company either doesn't actually have any money or has pulled a disappearing act and made themselves impossible to reach.
Basically, the reason to sign up for tiny companies with no reputation is to give yourself project experience. But it won't necessarily result in deeper wisdom about the process. It could just mean the boss is overconfident.
Going it alone, the obvious alternative, tends to whip game developers into a self-exploiting mode where they crunch really hard on features or assets, when they actually need to step back, make some painful cuts that throw out months of effort, and refocus their design to have better synergy. The push and pull of a team tends to mitigate those outcomes through earlier interventions, but without financing it's very hard to keep one going.
So, yes, the big companies do have advantages. The upside of the indie space is that it is more in line with the rest of the arts than a corporate career path - it allows the process to be something other than a production built off the back of a market survey. But that means a prerequisite is exposure to the arts and to processes that aren't strictly industrial design. This isn't a well-developed thing in the indie scene since the early influences they are working from all tend to be in the industrial design motif: addictive arcade games, sprawling epic RPGs, etc. Starting from these kinds of premises tends to scope the project incorrectly for the available skills, while simultaneously forgoing alternatives that no company would consider.