Depends on the state. For instance, in PA yes, they cover the legal side of things (at least to the extent that there isn't usually another lawyer involved in the process).
The other piece to this is that this 6% is split between the buyers agent and sellers agent. Typically, as a buyer, the person showing the house to you is _your_ agent (versus the UK where it is the seller's agent). Put another way, there's effectively a whole extra person involved who (at least legally) has a specific fiduciary responsibility to the buyer, and who takes on _some_ of the tasks that otherwise might fall to a selling agent.
It's also worth noting that there _do_ exist "discount agents". For instance, Redfin will charge sellers 1-1.5%, and if you use them as a buyer's agent, they will still charge 3% (since it is effectively baked into all prices) but then rebate you 1.5%. But this is less common.
So yes, overall, realtors here are doing more overall, but honestly it's largely (I think) just that they make more here because they've been effective at establishing norms, and also because small percentage point differences are easy to discount away. For instance, I'm currently buying using a traditional agent, because honestly the 1.5% fee difference is outweighed by the savings you can get with someone who can work better on offer price and post-inspection negotiations, and who is going to be someone the listing agent _wants_ to work with (which they will pitch to their clients as "this person is reliable and will ensure we close, whereas Redfin are useless and the deal might fall apart").
Not saying it's good, just giving more of the landscape.