I agree if it is percentages like 30% to 50%. Also because the kind of content-creators needed for advanced mesh building (which obviously is more reliant on expert knowledge than making the layered system clothing that once was the standard within SL) often have their own standards for selling stuff they build elsewhere, even hobbyist builders. Percentages like that would seriously offend a lot of them.
Sansar isn't born in the same environment that SL was, in the early years at the start of the century, when everything could be sticks and blocks and still be exciting to a lot of people. We have higher standards, now. We have to see it could be like the Witcher and GTA V. To even get people now playing SL to start using the new platform, it is necessary that Sansar offers things of a similar or higher level than SL does, currently, right from the get-go, almost. People take their mesh avi's and AO's and sex beds etc. for granted, now. If they need to get that stuff again, but they get some cool new stuff as well, they probably will. If those things COULD theoretically also be around in Sansar (maybe even better), but they are just not there yet, because content creators haven't made them for it, yet, I bet many SL players will quickly turn their heels, log out and get back to SL. And of course, they will want MORE than just SL players to flock to Sansar. So the bar is pretty high.
I am a bit worried that, somehow, they think they are still in 2002. That they can just do the same thing again. They'd be wrong, I fear. I get that SL grew to be what it was not because of what Linden Labs made, but because of the freedom it gave it's users to make stuff. But they can't just offer 'potential' only and expect creators to make everything from scratch after they open the doors to the new playground. Because there IS another playground already. It has to be pretty, interesting, cool, from the start, so users will come. Without users, many content creators are not going to be all that excited to start making stuff for Sansar. So, Linden Labs really NEEDS to real those creators in beforehand with the promise of new options AND new users.
So, yeah. Kicking them in the nuts with a sales-tax of 30% or more would be really counter-productive. Then again, if you look at the amount of stuff sold on SL, they could make that percentage far smaller, far more reasonable, and still make more than they make on land in the SL business model (given the same amount of users). Would also help if the sales-tax was more transparent than it is in SL (with that whole selling/buying lindens difference stuff, say), that it was a fixed percentage so that if person A paid 10 dollars in virtual money on day X, the other would be sure to get, say, 9 dollars if he cashed the virtual money in for dollars right away (if it was, say, 10% in tax). Would make it more transparent, certainly.
I don't think it will be a flopasaurus because of that. I haven't heard them name percentages like that. I am more worried about whether Sansar will be 'user-ready' enough when it opens up (as you said, no users, no market, and thus few creators), and about how they market it, show of it's potential. I did quite like the elephant vid above, but most of what I have seen, demo-wise, has been somewhat underwhelming. I mean... they walk around with avatars in those vids? I get that Linden Labs has always been careful in using the products of content creators in their vids and demo's, for obvious reasons, but... really. Why don't they get the guy from Vista to at least make them some half-decent animations for walking, so those avatars don't look like idiots doing a dork-walk, for God's sake!
I often feel that the folks at Linden Labs only ever half-understood their product.