Triumph's aren't the only motorcycles that have teething problems, they all do. How'd you like to be riding a GS beemer and have the Para lever (rear drive casting) break in two.... Happens. Or ride a HD and have the camshaft bearings come apart and destroy the engine... Happens. Or have your Kawasaki turn into a 2 wheeled toaster because some flunkie routed the harness wrong and it rubbed through on the frame and shorted out..... Happens.
A motorcycle is a complicated machine, made up of many sub assemblies both electrical and mechanical and machines fail, from both wear and human error. To err is human and humans design and assemble these machines.
Just buy what you want. Most never need any warranty related service but when they do, Triumph has been stepping to the plate and handling the problems in warranty or not.