The game relies on scarcity of the good stuff. And it being less scarce for Rt.
A 0-slot stardust cannon would still need the token equivalent of tens of bossfights.
The 2-slot would need to be enough grind to match up to the 500 Rt or so it would cost you to get it out of the gara.
It still needs to be enough "work" to be worth what it would cost in Rt. Dunno what your minimum wage is like, but here that's about 5 hours tedious work to equate $50, You want it to be harder than using that real money, so say 10 hours bossgrind for a 2-slot stardust cannon.
Rt needs to have value, making it cheaper than the time the grind would cost is on way of doing that.
I would agree with you if there was a trading system, but there is not, nor or are there any plans of one as far as I know. If there was a set price for said stardust, I would be fine with that. But, just about everything good either requires a lot of time/money for a CHANCE of getting it. I just think it's stupid, and that it's a way of cutting corners. If the game is really fun, I should still be playing even if said Stardust Cannon cost 2000 UC. Also, it would not take $500 to get an Stardust Cannon, nor do people try to roll for it last I checked. A few posts ago, Choja was raging about getting one IIRC.
TBH, I just want a "cap" on the amount of time/money needed to get somthing. It's just unfair to the people who have ground the hell out of Haku, Berzy, and Frac, hundreds of times with little to show for it. The grinding doesn't give Cyberstep money, so I figured it would be easier to negotiate, though I think one should exist for Gara too.