It looks like a result with complex implications - eg, maybe making it impossible for new miners to set up unless they have a meaningful advantage in operating costs instead of just parity with the entrenched players. It is hard to tell because market reality is a mess but if there is a meaningful strategic choice to be made beyond simply announcing a block when it is mined then there is a lot of room for weird equilibriums even if the paper's specific analysis turns out to have flaws.
EDIT: For comparison: https://gridwatch.co.uk/
In ~6 more years, Bitcoin will undergo two more halvings, so if the price of BTC is not ~400k by then, then attack will have become more feasible.
--- Starting in late 2020, as shown in The Economist's graphic, the spot market in Bitcoin became dwarfed by the derivatives markets. In the last month $1.7T of Bitcoin futures traded on unregulated exchanges, and $6.4B on regulated exchanges. Compare this with the $1.8B of the spot market in the same month. ---
But who ultimately controls Bitmain? The Chinese state.
So, by extension, bitcoin is controlled by the CCP.
What a shitshow. Crypto needs to move on from bitcoin already, pick something better... anything better. There are so many options, and bitcoin is the worst of all of them.
The Monero PoW community has had to deal with such nonsense, as have other smaller PoW coins.
With ε=1e-3, the expected number of 6 confirmations works only so long as the largest pool size does not exceed 12%. For a pool size of 30%, at least 24 confirmations should be required in Bitcoin, but 49 in Monero with its stricter ε=1e-6. You can see the table and the math at https://gist.github.com/impredicative/0907e1699f5ff97a9fed5d... and again it's all cleanly reproducible from the whitepaper. Anyone who is still requiring only 6 confirmations then will be setting themselves up for a risk of reversal.
In fact, wiping out the derivative markets would be seen as a net-postive by most individual hodlers.