"Nintendo been relying way too much on their established franchises to sell systems and it obviously isn't working"
It's working. It may not be working amazingly well but it's working.
The Gamecube is selling on par with the N64 last I heard, it's still ahead of the XBox worldwide (despite MS burning money like mad trying to sell consoles - just think of how things would stand if MS wasn't willing to do so), and Nintendo is making a nice profit off of it.
The Gamecube isn't selling as well as it deserves but I think that has very little to do with the games.
"A hundred Mario spinoff games are not going to sell systems"
Where are you getting that? Of course they'll still sell systems. Mario Kart is going to be the biggest system seller the Gamecube has had since Smash Bros which actually boosted Gamecube sells exponentially in some markets.
It won't boost it to PS2 levels but, like I said, it's unlikely any game would.
I agree with most of what you're saying. The Gamecube needs more original franchises and Nintendo shouldn't rely entirely on its existing franchises but I just think you're completely wrong in dismissing the existing franchises as being powerless to sell systems and are over-estimating what orignal franchises could do for the console.
Camelot is highly rumored to already be making an RPG along with the Mario Sports titles.
It's not like it has to choose between just making Mario Sports titles and original games. It can do both. It can make games with existing franchises to sell systems NOW while creating original games that MIGHT someday be big after they get a few sequels.
Anyway, the whole point of Nintendo allowing third-party developers to use its mascots is it will allow Nintendo to free up its own resources to create original titles itself. According to Miyamoto, there are many such titles being developed now. They just haven't been revealed yet. I think they were supposed to be shown at E3 but they obviously weren't for some reason. I think maybe Nintendo was worried people would overlook the original games in favor of existing franchise games like Mario Kart, MGS, and Final Fantasy and it was probably right about that.
"Mario Golf and Mario Tennis are unneeded sequels and thus are a waste of a great developer that could be working on something new."
Maybe from your perspective but Nintendo and Camelot are companies and they mostly care about money so, if they really had to choose, of course they'd favor making games that are sure-bets to sell well and at least sell some systems instead of taking a risk that almost certainly wouldn't fare as well.
Grand Theft Auto: Vice City was sure as hell an unneeded sequel but I doubt Rockstar regrets making it.