By “loss” do you mean that of the exploiters losing tokens because the community decided not to follow the hacked chain?
The goal of all the shadow forks and merge testnets is to find the different edge cases and failure states to answer those questions of “what is the failure plan?” If mainnet merge somehow does not succeed despite these tests and all clients fail to produce blocks, the merge can just be delayed until the bugs are resolved. If mainnet merge succeeds but later a bug emerges, users can coordinate a change to revert the lost funds.
Loss could come in many forms. We can't predict that future yet, but we can be wary of it.
> the merge can just be delayed until the bugs are resolved
This is one of the losses. Every time the merge is delayed, price drops. Price is currently trending higher right now because the merge looks like it is on track.
Delaying the merge also has a loss... for the miners who are currently securing the network. aka: the bomb. The bomb is an embarrassment because every time it gets pushed out, that is essentially the minimum amount of time before the merge can happen.
> users can coordinate a change to revert the lost funds.
How. I want a detailed plan. So far, I haven't seen it.
You are conflating "people losing tokens" with "people losing the USD value of their tokens." It is very likely that the market becomes unpredictable before and after the merge, value of ETH may plummet or skyrocket, and holders of ETH should be prepared for that.
> The bomb is an embarrassment because every time it gets pushed out, that is essentially the minimum amount of time before the merge can happen.
That is not how the bomb works. It is a soft deadline. If the developers feel the merge is ready, they can initiate it before the bomb occurs, and miners will immediately be forced to transition their hardware to other PoW networks. If the developers do not feel the merge is ready, and the bomb is fast approaching, they can delay the bomb by another month or even a year and it will not have an impact on the timing of when they actually decide to initiate the merge.
If the worst that can happen is "embarrassment" for having to delay the merge again to fix a critical bug, I think you are overblowing this. The developers will happily delay the merge until all the bugs are fixed, and the users are happy to have this happen as they would rather wait for a working merge than rush toward a broken one.
> How. I want a detailed plan. So far, I haven't seen it.
Every time the protocol rules change, developers are activating a fork by coming to consensus on the new rules - all client software must coordinate code updates to match the new rules. Eth core developers and client teams have been doing this regularly over the years, and especially during the approach to the merge. They can coordinate a revert or fork, just as they have coordinated the past several forks[1], to fix these issues.
It is fine to imagine a hypothetical failure case for the merge but this does not mean "it cannot be fixed." It might be messy, the value may drop, coordinating the fix may take some hours or days, and it is even possible the chain stops producing blocks for some short while if it is very catastrophic. Users still holding ETH going into the merge should be prepared for these situations, it is probably the most significant development in crypto currency and DLT since the Bitcoin genesis block.
The goal of all the shadow forks and merge testnets is to find the different edge cases and failure states to answer those questions of “what is the failure plan?” If mainnet merge somehow does not succeed despite these tests and all clients fail to produce blocks, the merge can just be delayed until the bugs are resolved. If mainnet merge succeeds but later a bug emerges, users can coordinate a change to revert the lost funds.