Uhhh, I don't think so... I've yet to see one of these "bulletproof" sailing yachts of which you speak... :-)
Whatever parts you 'worry about' breaking such as the Steering gear or the boom-mast attachment can be made stronger than required with very little weight penalty. Without building a battleship.
Well, that may be true of your boat, but most of the overbuilt battleships I've sailed, or seen, are barely capable of getting out of their own way under sail in lighter air, and are often seen 'sailing' on perfect days using this rather curious 'sail configuration'...
Ha ha...... yes good wind as well, but plenty of 40 footers do that too ! It's the owners prerogative. When I was in the Carribean I saw a lot of people motoring even performance multihulls, cheap fuel ! My boat sailed St M to St John at 9 knots most of the way under one big headsail alone and Passed people motoring! There's some funny sailors around.
Uh-oh, don't get me started on hydraulic steering on sailboats... One of my least favorite features on many larger yachts, sailing without feedback through a wheel or tiller IMHO is akin to having to wear MULTIPLE condoms... :-)
Never the less it works, it's easy to fix and it can be made pretty reliable with a pressurized reservoir and a pressure gauge in view of the helm. Any pressure drop is an early warning. It's a good system. You can also get positive feedback hydraulic helms now.
Well, I realize windvanes have almost completely fallen out of favor these days, .....
Sorry, but that's simply an example of poor seamanship, and a misuse of one of your pieces of equipment... Sailing to a vane in coastal waters or within range of other dangers, then going to sleep, is begging for trouble, bigtime...
Not to mention, an autopilot is not immune to producing a similar result...
Oh I make no claim to it being my finest hour
But I was exhausted and sick and not caring I went below for a little rest...and slept and slept. It's easy to do.
BUT I would have been better off with a functioning autopilot then rather than a functioning wind vane , that's all.
These days you can program an alarm for course deviation on another bit of electronics so it keeps an eye on the Autopilot and sounds an alarm if you are off-course. I really like the navigational gear these days.