Some of what you say may be true (though I think you can easily argue that SMC forced their way in as an at large largely based on RPI), but I think you need to think a bit more holistically about this.
Remember when the MVC "cracked" the RPI a few years ago and got something like 4 or 5 teams into the tournament?
A big part of that was smart scheduling up-and-down the conference. If all the teams in a conference schedule smartly and hold up their end of the bargain in terms of winning games they should win, you can end up in a situation where playing conference games actually HELPS team's RPIs rather than hurting them.
If the WCC can get to a place like that (and it's really not a total pipe dream), it's much more likely we'll be getting multiple teams into the tournament, which equates to more $$$ for each team in the conference.
So, I disagree... I think RPI matters very much, even for teams that won't likely be making it to the tournament as an at-large bid.