Its a little bit of a complex situation.

Each machine usually has a negotiated timed license. Which means they can make the machine until that license expires. Stern also makes games pretty much to order. Meaning their distributors take pre-orders and maybe order more based on demand. That demand will dictate whether a game will be put back on the manufacturing line again.

So if a game is popular, it means they will keep making them until the license expires and then maybe renegotiate an extension (unlikely). Other games don't really sell all that well and they end up not even making all the LEs. If their distributors are sitting on unsold NIBs, its unlikely to get run again even if they have the license for another 3 years.

I don't think waiting a year is crazy if you are happy with a premium instead of an LE. You can always at least wait until their NEXT game is out and the lions share of hype/NEWness has worn off. You also might get the opportunity to grab one second hand from all the 'Buy Everything' crowd once that newness wears off.

Also, don't forget you can probably pick up a lightly-used machine even after it's out of production.

Historically, your risk is actually very low waiting a year. I think it's highly unlikely you'll have a problem getting B66 a year later. There's usually only a rush if you want an LE. In some cases, there's not even a rush for those. I'd be surprised if B66 wasn't produced for 2 or 3 years.