That knowledge base was also possessed by the folks writing it, and the playtesters, and they constantly went back and tested against a fan base with that same shared base of knowledge & preconceptions through the playtest.
It's assumed, and it's deeply ingrained, and that's a big part of 5e's success (and the relative lack of edition warring against it).
There's almost certainly people with that knowledge, right at the table, spouting it freely the whole time. (Indeed, try getting us to shut up, it ain't easy!)
No, the first step is for the DM to make a ruling. he may or may not work his way through each past edition he's familiar with to help him pick the best ruling, but it's likely, that any such past knowledge informs his ruling.
In other words they should listen to the old guy mumbling in the corner: "I remember back in the day when we rolled 3d6 for ability scores, and we liked it! None of that namby-pamby fancy stuff! And we had to walk to the game up hill. In the snow. Both ways. Fighting off the orcs with our spiral ring notebooks!"
Although it is kind of funny. In another thread you're pretty vehement about skill challenges not being part of the rules. Cherry pick which rules carry over much?
