One versus two-piece backs

[rcc56]

The primary causes of center seam failure are environmental, usually insufficient humidification or thermal shock.

I like the look of a one piece back with a strong narrow figure.
I once bought an unplayable fiddle just because I liked the back. Fortunately, when I fixed it up and got it into playable condition, it turned out to be a pretty good instrument.

In the violin world, a violin with a really well figured one piece back brings a higher price than one with a two piece back with similar figure. And violin suppliers are known to charge more for the raw wood.

[journeybear]

Maybe I'm missing something, but as I've been thinking about this lately, more than I ever had before, I've started wondering why two-piece backs are so much more common than one-piece backs. Is it something to do with wood supply? That is, the availability of boards that are wide enough? Tops are made from one piece of that width, right? Are there not enough wide enough boards around to supply builders with material for one piece backs as well? They're typically made from different woods, aren't they, so there wouldn't be a problem with supply, right? What am I missing?

[sunburst]

The primary causes of center seam failure are environmental, usually insufficient humidification or thermal shock...

Maybe, but I suspect the primary cause is poor joining and gluing.