I have an awesome picture of me, aged 3 in around1979 dressed in dungarees, boots and a lumberjack coat and playing with Action Man.
Certainly where I grew up, economics played a huge part in the non-gender specific toys. Toys weren't mass produced in China and supermarkets were yet to sell cheap clothes. So clothes were hard wearing, passed between children and the same went for toys.
Of course there were dolls and prams, but I don't remember pink and blue sweeping brushes marketed at different genders.
Things are so cheap now, and companies try to sell as much as they can, so why not sell a pink sweeping brush to a girl in the hope the parents will buy a blue one for their son? I don't agree with this approach of course, but it explains the change I think.
If we all voted with our cash then things might change, but it is actually very different to buy stuff that isn't blue or pink.
I have two sons and both will happily play with dolls, prams as well as guns. I have tried to bring them up in a feminist way but the older one, now in year 1 has picked up all sorts of sexist views at school. Having said that, because my sons have always had female GPs, they think all doctors are girls. This might be as damaging for their career prospects as assuming all would be men.
There is also quite a bit of guilt involved too. No parent really wants their child to be ostracised at school, so if there is peer pressure to be pink it is hard to resist. I know my heart sank when I moved to my current city from a small village, where children wore generic t shirts and shorts to pre school football sessions. At our first football session in our new city, without exception the 5 year olds (and younger) were head to toe in the city replica kit. So I will probably buy the same for my boys, because I don't want them to suffer socially.