From Richard Murphy:

[Have Domino's Pizza] discovered that people actually don't like that much choice and really don't want to wade through multitudinous, and often quite similar, choices? If I was Domino's I would be giving serious thought to this.

As a mover and shaker in retail (i.e. I push a trolley and suffer from essential tremor) for two and a half years now, I can say that expanding and contracting menus are probably tactical.

That is, in competitive conditions, one should pull out the shiny things to attract customers from your competitors. In [near-]monopoly conditions, the shiny things are just cannibalising the sales of your own core lines, so get rid of them.