Try common sense, AnthonyGA, rather than using what little totally inadequate 'knowledge' you might possess about large airline ops.
Unless airlines are giving pilots comprehensive training in the hundreds of types of smells that one might sense aboard an aircraft and what they mean, I doubt that they are any better at recognizing an overheated bearing than I am. And historical incidents prove that pilots often don't know where a smell is coming from; and if they are prudent, they treat strange smells as potential fires or chemical contamination, as they should. If they are imprudent and dismiss unidentifiable smells as harmless, sometimes bad things happen.
Even an airplane mechanic might not recognize the smell unless he has already encountered it in the past. And pilots are as different from aircraft mechanics as I am.
It's not really a question of airline ops; it's a question of fire safety, which crosses the boundaries of all industries. Airliners are particularly vulnerable to fire, but beyond that, the general principles of fire safety still apply.