This is an interesting thought. Yes, you could sell a “total conversion mod” that is essentially a different game but with new content. What you are suggesting here is that Radiant would get some additional money by selling the “engine”… presumably to some customers who don’t even own Stonehearth or perhaps do but for the “vanilla” game alone.
I think the cost of Stonehearth will likely continue to be low enough that simply requiring those who want to play a “total conversion mod” to shell out the bucks to Radiant for buying the vanilla game would be worth it. The only potential loss of income to Radiant might be for those few people who might have purchased both the “mod” as a completely new game (with the Stonehearth engine) as well as the vanilla game separately.
Presumably if you are bundling “the engine” with the new game, you would be asking Radiant for a discount for bulk quantities of their game and establishing independent distribution channels for the engine as well. I’m also considering on the business side where the people selling one of these total conversion mods will want to keep the price of the content + engine at a point similar to what Stonehearth currently is at… perhaps a little more expensive but not significantly so. That sort of defeats the whole point of Radiant selling their game and in the end I would think you would do much better simply by selling the “mod” as a separate package.
Of course this presumes that Stonehearth is going to be phenomenally popular with sales in the tens of millions of copies and Radiant laughing all of the way to the bank. If Stonehearth is a flop as a game, it might be useful to take the “engine” and add new content trying to market the game in a new way with a fresh approach… where paying for the “engine” could be worth the trouble. At least from a business perspective, I would think paying for the engine separately would only be really useful if the game was a flop or Radiant is interested in moving on to other projects with Stonehearth already several years old.
Yes, I’m aware of some companies who sell their game engines… usually source code with NDAs and other things attached though. That this idea is even being presented shows a little bit of the extreme nature that Stonehearth seems to be going in terms of its development.