Stredda
Runs naked through virgin scrub
Like mountain bikes there will be (and already kind of is) a wide and varied range of gravel bikes to suit what you are looking to ride. As @rowdyflat mentioned you don't need wide tyres for a lot of riding if a lot of the road is sealed or champaign gravel.
Racers seem to be going wider as on less that optimum gravel, the wider tyre does actually roll faster due to the MTB tyres being able to run high TPI casings, which gives a softer side wall and because of the extra volume, the puncture resistance is improved over a narrower gravel tyre with the same TPI.
Also, if comfort is a priority, wider tyres are preferable.
All just depends on what you want out of your bike.
Racers seem to be going wider as on less that optimum gravel, the wider tyre does actually roll faster due to the MTB tyres being able to run high TPI casings, which gives a softer side wall and because of the extra volume, the puncture resistance is improved over a narrower gravel tyre with the same TPI.
Also, if comfort is a priority, wider tyres are preferable.
All just depends on what you want out of your bike.