Because when there are lots of companies producing lots of different machines, you get more variety. Yeah, Stranger Things and Elvira are boring fan layouts, but look at Jurassic Park, Iron Maiden, Beatles, Willy Wonka, TNA, Rick and Morty, Oktoberfest, Houdini, Deadpool, etc.

So...I'm not sure what you're asking for here. Have only one game released per year, but make it so special and catered to your tastes that you will be sure to buy it (and not have to suffer through releases of games that don't interest you)?

Which era of pinball would you prefer to be living in? If you don't need a new machine every 3 months, then you're living in a great time for pinball. Once per year, just pick your favorite of the 10 machines released in the last 12 months and buy it.