How much in commission can one possibly be for any one who restores lost bockchain accounts?

You’d have to show me it were possible first, which I kinda doubt it is.

It could be a huge total. Especially from early bitcoiners who weren’t taking it seriously

Not a thing.

Chainalysis, a blockchain data platform, 17%–23% of the overall Bitcoin supply might be lost, which ranges between 2.78 million and 3.79 million BTC.

I think @Forever_Free has given a fairly accurate range for scope of the total value of bitcoin assets that are now considered “lost”.

As far as the commission fees typically charged by consultants who claim they can recover inacessible bitcoin, at least one source puts the rates at between 5% – 40% of the amount recovered :

https://www.investopedia.com/news/20-all-btc-lost-unrecoverable-study-shows/