Gendered terms — particularly female — being replaced by neutral equivalents?

I think the main reason why gendered terms tend to fall out of use is a tendency to symmetry - we have so many words for professions in English that never had a gendered form, eg. 'teacher' so that the few forms we have look more marked than they are.

In a language like German were there is a productive suffix for female gender, eg Lehrerin (teacher+fem) this symmetry already exists. And since there is a possible gendered form for every neutral form in German, gendered forms are not that exceptional.
There had never been a female Bundeskanzler of Germany before 2005, but it was self-evident that Angela Merkel's title would be Bundeskanzlerin.

I believe this happens because it is seen as at best unnecessary and at worst patronising and discriminatory to distinguish a woman's profession because of her gender. There's no such thing as a pilotress or doctoress/doctress. It is on the same lines as using Ms instead of Miss/Mrs - a woman's marital status should be irrelevant in all the same circumstances where a man's status is irrelevant.

Unfortunately most professions are already masculinized, as evinced by their masculine endings and the fact that they used to be the exclusive province of men. Adding a feminine ending draws attention to the fact that this is something a bit 'different' and 'other' away from the 'norm' of being a man. Even 'human' and 'woman' have their roots in 'man' - which is supposed to be a gender neutral term for all of mankind but which, in English at any rate, relates specifically to male people and a subconscious emphasis on maleness as normal and female as 'other'.

I also think it would be a massively uphill struggle to get the world to switch to neutral terms like 'doctum', although where I work no one uses Chairman/woman any more, but simply 'Chair'. Using a female ending doesn't diminish a woman's actual ability, only prejudiced people's perception of it. Far better to ignore any original masculine endings and absorb them as neutral terms instead.