One detail most comments seem to be missing is that the O(1) complexity of get/set in hash tables depends on memory access being O(1). However, if you have a memory system operating in physical space, that's just not possible (you'd have to break the speed of light). Ultimately, the larger your dataset, the more time it is going to take (on average) to perform random access on it. The only reason why we "haven't noticed" this yet that much in practice is that we mostly grow memory capacity by making it more compact (the same as CPU logic), not by adding more physical chips/RAM slots/etc. Still, memory latency has been slowly rising since the 2000s, so even shrinking can't save us indefinitely.

One more fun fact: this is also the reason why Turing machines are a popular complexity model. The tape on a Turing machine does not allow random access, so it simulates the act of "going somewhere to get your data". And as you might expect, hash table operations are not O(1) on a Turing machine.

Ah, the age old question of "1 horse-sized duck vs. 100 duck-sized horses"...

As others have mentioned, the main problem is that open systems are more vulnerable to low-cost, coordinated external attacks.

This is less of an issue with systems where there is little monetary value attached (I don't know anyone whose mortgage is paid for by their Stack Overflow reputation). Now imagine that the future prospects of a national lab with multi-million yearly budget are tied to a system that can be (relatively easily) gamed with a Chinese or Russian bot farm for a few thousand dollars.

There are already players that are trying hard to game the current system, and it sometimes sort of works, but not quite, exactly because of how hard it is to get into the "high reputation" club (on the other hand, once you're in, you can often publish a lot of lower quality stuff just because of your reputation, so I'm not saying this is a perfect system either).

In other words, I don't think anyone reasonable is seriously against making peer review more transparent, but for better or worse, the current system (with all of its other downsides) is relatively robust to outside interference.

So, unless we (a) make "being a scientist" much more financially accessible, or (b), untangle funding from this new "open" measure of "scientific achievement", the open system would probably not be very impactful. Of course, (a) is unlikely, at least in most high-impact fields; CS was an outlier for a long time, not so much today. And (b) would mean that funding agencies would still need something else to judge your research, which would most likely still be some closed, reputation-based system.

Edit TL;DR: Describe how the open science peer-review system should be used to distribute funding among researchers while begin reasonably robust to coordinated attacks. Then we can talk :)

But the thing is... except for the original authors, none of these papers so far really claim to have a room-temperature superconductor, right? They claim "simulated band structure with low Fermi level", or "unusual levels of diamagnetism", or "almost zero resistance up to -100°C (but lack of phase transition)", etc.

Yes, retracting these is still shameful, but it's not a "we found extraterrestrial life" claim. It's a "we received weird signals from a nebula that we don't understand so far" claim.

And yes, a lot of supporting but inconclusive evidence is still supporting evidence. My point is not that (most) scientists would risk lying about replicating a superconductor, but rather that uncertain or inconclusive results with a solid chunk of plausible deniability in a rapidly evolving environment go a long way towards being "in the room where it happened".