I read before Carnival glass invention , the iridescent glass was ultra expensive. But suprisingly they use one process step same with the Tiffany glass , the spraying of tin chloride on to hot glass. Tin chloride is cheap but I think lowering the expenses depends of no use of silver like in the glass alloy at Tiffany Glass Studios. And use of molds not hand blowing the glass at 1920s Carnival glass. Tiffany or more correctly his chemical researchers Nash - Son and Father - was famous to add lots of gold to produce the rail system red stop light. It was secret and everybody asking why they were requesting lots of money to produce red light glass. I think they were the last artisans who wants to produce the best like Faberge. Look at todays jewels , glass art , watches , cars, yachts...