Steam caters to a wide verity of gamers but wargaming is dead to all but a very small number of developers and distributors. The only wargame I can think of that Steam has is the Hearts of Iron franchise and I don't necessarily consider HOI a true wargame (more of a expanded risk). Steam is looking for large sales numbers and games found at Matrix and others will never touch the games sold by Steam that cater to the what's in this week crowd. Also the level of support I've seen and experienced at Matrix is otherworldly compared to Steam.
Of course it's good for them to be the provider of very popular and widespread games. But I doubt that "reaching a big audience" is a criteria for any single game. I guess it's more like "something for every niche gamer".
Especially during the last year you see tons of indie games on steam. Even right now, if you check the "new releases" most of the stuff is niche indie games. Frozen Synapse or Geneforge aren't any games appealing to the masses.
But of course there is some math to be done. It has it's reasons why very special programs are extremely expensive. I mean, if you are a company wanting to buy a program for managing an oil derrick you will need to spend thousands of dollars. And of course the company writing the program will not get any more sales if they sell it cheaper - as you wont reach any additional customers and the oil companies need to buy your specialized software anyways.
And I guess it's similar with Distant Worlds. I can't imagine, that steam would allow DW to cost more than 60 bucks on steam and even that would be extreme. 40€ for the "compilation" would probably be more realistic as a "steam price" of such a game. For Matrix Games that might mean that they can't offer the game for 80€ on their homepage anymore.
Lets assume they only get 50% of each sold copy then. That would mean that they need to sell double the copies as before (roughly, not considering steam charges and whatnot but you get what i mean). While that seemed to work for spiderweb (as they would not have continued doing that) that might not be the case for DW. And that is a risk they would need to take of course.
At that point I want to throw in some snippets from Jeff Vogel (Spiderweb)from http://jeff-vogel.blogspot.fr/2011/08/avadon-is-out-on-steam.html
The Steam Thing does mean that we are embarking on a great experiment, something that we never planning on doing. But, the way the online games market is moving, something that seems like the right choice.
Avadon: The Black Fortress Is $9.99 On Steam
I've written a lot about how I think it's important to not price niche games too cheaply, and I stand by that. However, at the same time, Avadon will be only ten bucks on Steam, the cheapest we've ever made our newest game for PC/Mac. Why?
1. Steam felt it was the best price. I went into this trusting their judgment, because they know a lot more about selling Indie games than I do. When you're an Indie and Steam comes knocking, you don't say no.
So I'm charging $10 on Steam and for the iPad. By the standards of that market, it's a hefty price, enough for me to earn my living. It's cheap enough to work as an impluse buy. It isn't the $1 or $2 price that I'm still sure would put me out of business.
This means I need to adjust the prices I charge on my own web site. I have changed the price of Avadon to $20, and in the future we will very likely reduce the prices of our earlier games as well. Our next game, Avernum: Escape From the Pit will start out at $20. If this grand experiment works well, we may make future games cheaper still, though I doubt any new game on our own web site will ever go below $15.