Why regret
The sys1 were unfixable back in the 70s
Who would know that somebody would create new boards to run these games?
Your father ran a business, if something was not profitable then dump it!
The only regret I have is that my father gave away, sold for peanuts or threw in the tip (cos no one wanted them) HUNDREDS of pinball machines, bingos and arcade games. Giving them away or selling them is fine - but - if the larger of the two storage building was not leased back in the early 90's, all these games would still be there. The 90 bingos in one day was something I'll never forget. If I could erase the memory of loading the Truck for a solid week full of system 1 games, Sterns and Williams system 4/6 then I'd have no regrets.
I think the other regret I have is not starting the restoration business earlier.
maybe I should have used "pinball disappointments" instead of "pinball regrets"