The canal was blocked for 6 days and revenue is $15 million per day, so that's $90 million. But many of the ships that were held up eventually transited anyway, so $90 million is an absolute upper bound. Then there is the cost of the operation to free the ship, which I don't know. But Egypt is asking for $1 billion, so the rescue operation would have had to cost at minimum $900 million for the price to be justified. And I know it didn't cost $900 million, because if split evenly over 6 days that would be $150 million per day, which would be > 50% of Egypt's entire government spending over the time period. So I can say with confidence that the rescue was at least an order of magnitude less than that, so another $90 million (and that's still a massive over estimate).

So absolute upper bound for losses is $180 million. If I were making odds I would guess that only 1/3 of the ships diverted around Africa, so $30 million, and that the rescue cost another $15 million, so over/under $45 million.

And that's without even bringing up that there was a canal pilot on the ship at the time who may share some portion of the responsibility for the accident. So, yeah, it's extortion.

Egypt is likely using treble damages in their calculation.

A pilot from the canal was on board, how is it not their fault? (Zero compensation)

I don't know the rules of the canal, but I highly doubt this scenario. The Egyptian gov't basically has a monopoly and can charge anything they want and write any rules they want. Of course, ships are free to circumvent Africa (around the Cape of Good Hope) if they disagree.

More likely: Ships are required by rules to have an Egyptian pilot on-board during the passage, and there is limited legal liability for ordinary operating circumstances. That said, if an Egyptian pilot was found grossly negligent of their duties, then they would be liable. However, in most legal systems, this is an exceptionally high bar. And, I assume if you pass the canal, you subject yourself to the Egyptian court system. (Read about the big cruise ship that ran aground in Italy. That story reads like text book gross negligence!)

Per the Suez Canal Authority - Rules of Navigation Article 4, section 7 (page 7):

“(7) Owners, mobilizers, charterers and/or operators bind themselves responsible for any mistakes resulting from pilot’s advice or arrise by SCA personnel.”

https://www.suezcanal.gov.eg/English/Navigation/Pages/Ruleso...

The pilot is supposed to steer the ship, but the captain is ultimately responsible for it.