Is there a meaningful distinction to be made between the system and the content?

[PhoenixPhyre]

It's worth noting that the 'death-is-easy' feel of GURPS is a product of the system that GURPS uses rather than any sort of tonal choice on the part of Steve Jackson games. It has to do with how the model system that is GURPS functions and unless you distort the numbers massively beyond all expectations it will always be that way. It is a solid example of how the mathematical model that 'the system' actually is constrain game options on a purely mechanical level.

A TTRPG system is ultimately a set of mathematical models (often bad ones), and the structure of those models constrains the possible permutations of the game, including through such things as the choice of dice to use, since different RNG setups produce different output curves. Ultimately any time you use any mathematical system at all this introduces constraints on the content of some kind.

Agreed. That's what I mean by a system-imposed constraint on content, and it's part of why you can't really get to 0 very easily at all. System and content are coupled at some level > 0 -- systems set tone and feel just by their basic action resolution system. In some ways, 1d20 + Mods >= TN imposes a different feel than 3d6 + Mods >= TN which is different than the feel a dice pool/counting successes system imposes. And most systems are more involved at this level than just that.

At the other end, you always have some freedom--you can hack games to do things that would never have been expected or supported by their authors. Just like you can build very different games on the same video game engine (although some similarities will remain).

The endpoints are "off the scale", but serve to define the extremes.

Edit: I wouldn't say that the models are bad. All models are wrong. Some models are useful. And some models are useful in certain circumstances but not others and for certain purposes but not others. Fit-for-purpose gives a lot of leeway, especially when the purpose involved is really broad.