I really don't think all politician have aspirations to become leaders of their party, they become politicians for all sorts of reason and some are more ambitious than others.
Take Julie Bishop, she would be a viable candidate to lead the liberals and has had opportunities to do so in the past but it looks like she is more than happy with the position she has held for some time and don't want the responsibility of being leader.
There would be few female MP's that could seriously think they may become leader one day, simply the odds are very much against them.
It takes special qualities to be a leader and not all politicians have those qualities and most would be realistic about that.
I think Morrison would like to lead but he is realistic enough to know he is not quite ready, I think Porter is also ambitious but smart enough to be patient and work his way up
