Paradigmatic surprises vary a lot in how dramatic they are. X-rays and double slit deserved WAY lower probabilities than 1%. I'm basically going on how convincing I find the arguments for uploading first and trying to maintain calibrated confidence intervals. I would not bet 99:1 against uploading happening first. I would bet 9:1 without qualm. I would probably bet 49:1 I find it very easy to tell personally credible stories (no outlandish steps) where uploading happens first for good reasons. The probability of any of those stories happening may be much less than 1%, but they probably constitute exemplars of a large class.

Assigning a 1% probability to uploading not happening in a given decade when it could happen, due to politics and/or revulsion, seems much too low. Decade-to-decade correlations could be pretty high but not plausibly near 1, so given civilization's long term survival uploading is inevitable once the required tech is in place, but it's silly to assume civilization's long-term survival.

I don't really think that outside views are that widely applicable a methodology and if there isn't an obvious place to look for one there probably isn't one. The buck for judgment and decision-making has to stop somewhere, and stopping with deciding on reference classes seems silly in most situations. That said, I share your concern. I'm sure that there is a bias in the community of interested people, but I think that the community's most careful thinkers can and do largely avoid it. I certainly think bad outcomes are more likely than good ones, but I think that the odds are around 2:1 rather than 100:1.