Thanks for your interesting contributions!
While this thread is hardly representative of worldwide chefdom, there seems to be a consensus that a small menu is actually desirable and more often than not a sign of quality food being served.
For many years I've been very aware of the fact that smaller menus will rarely, if ever, result in reduced sales. In actual fact I would consider this to be common knowledge throughout the industry, which is why I'm immensely surprised that so few restaurants in my neck of the woods (Germany) actually follow this bit of advice. There are hundreds of restaurants in my region alone that attempt to be all things to all people, serving bad-to-mediocre food through humungous menus. Even those restaurants which have scaled down their menus somewhat have retained the stuff that everybody else sells, i.e. breaded industrially produced pork schnitzels with industrial chips and random salad mixes with heavy pre-fab mayonnaise dressing. The schnitzels are invariably deep fried from frozen, and everything is sourced from major cash & carry outlets.
Almost 100% of these restaurants are family-operated; many, if not the vast majority struggle to survive. They battle on by paying rock-bottom wages, reducing staff, doing most of the work between the family members involved. Yet they all sell the same bloody stuff, thinking they're going to lose what little business they've got by radically cutting down on menu items, objectively improving quality and repositioning themselves somewhat outside that market. I just don't get it.
This situation is particularly rife outside the metro areas. Just like anywhere else in the world, you will find decent restaurants in the cities. But here in this particular region, which is quite touristy and a popular hiking and cycling destination for fairly affluent people from the surrounding cities, my restaurant, strangely, is one of perhaps two within a 40-mile radius that has a small menu and uses local meat and produce. I do hear from tourists frequently that they'd never expected to find a restaurant like mine in this region. That's not to say I'm getting rich here, as the locals by and large eschew my offering, so winters tend to be painfully slow.
I think my menu is as small as I can get away with; in a good metro location I would probably dare reduce it even further and make a spectacle of it.
As regards food trucks, I'm in two minds about it. Here in Europe, especially in London, it's a fad, with food ranging from downright awful to very innovative and delicious, lots of very authentic ethnic street food, but also the usual chippie vans etc. As a general concept, it looks very appealing to me, as it significantly cuts down on many of the costs involved in a running a brick-and-mortar joint. I do know, however, that there must be a reason why many of the more successful (and/or ambitious) street food vendors eventually start up proper restaurants/bistros. It's simply the real thing.