Not everyone has US $2,350 handy. Not everyone has the time and money to visit the U.S. Consulate for the second visit. Thus it is not true that 'you can always rescind your citizenship'.
Also, your 'no intentions of returning to live in the US' is incomplete. Some US citizens have never lived in the US, do not want to be US citizens, but are so because one of their parents was a US citizen.
You're aware this discussion is about wealthy people trying to avoid taxes? The person who doesn't have $2350 handy is the person furthest from this conversation.
I am aware that this specific thread, started by tonfa, concerns how non-resident US citizens have a tax obligation to the US.
I am also aware that the billionaires and multimillionaires that this article is about would need to pay taxes on their unrealized capital gains (part of the 'exit tax' shiroiushi earlier in this thread pointed out).
The article also points out that avoiding taxes on unrealized capital gains is one of the reasons for these fuck-you-got-mine people to move, which means the US $2,350 you quoted is an abstract lower bound, and not meaningful to the thread topic or the people involved.
Also, your 'no intentions of returning to live in the US' is incomplete. Some US citizens have never lived in the US, do not want to be US citizens, but are so because one of their parents was a US citizen.