I think it’s more that the production lines that existed to build them in volume have all been long dismantled, so it would be prohibitively expensive and all the people involved would be doing it for the first time.

And even if you found the money to resurrect the production lines, modern regulations probably wouldn't look too kindly on making new consumer goods with several pounds of lead in each unit. Better set aside your morals and enough money to buy some politicians while you're at it.