I was in part responding to the idea that women get to choose to work lesser hours therefore it's fair they get paid less. Many women don't work lesser hours and the roles they more frequently work in are often lower paid per hour.
The reasons for this are varied and complex, but a significant part of that is the 'higher paid' STEM roles are seen as unattainable for women more than for men - even given a broad background of socio-economic factors.
Women are more likely to be channeled into nurturing or service roles such as teaching, nursing, childcare or aged care, rather than more lucrative roles such as sales or STEM roles. At the lower end of the economy, they are more likely to be a waitress than a construction worker - guess what pays more. Yes being a construction worker may be more physically demanding - but being on your feet all day waiting tables isn't being slack either. In Australia, tradesmen are some of the best paid people, I can assure you that the 'professions' for working class women are not paid nearly as well, they are likely to be a hairdresser or beauty therapist or a masseuse.
And you can bet that the construction industry is unwelcoming to women in very similar ways that IT is. I can tell you I've experienced both first hand having started in Architecture and worked directly on building sites as well as moving into IT and working directly with programmers and other IT types from the position of doing both Tech Support and now as a Systems Analyst.
You say that programming jobs aren't lucrative - that is a relative term. They may not be paid as well as a top performing sales person or someone in finance or banking - but they generally pay better than nursing or teaching or any of the personal care professions women tend to get pushed towards.
It has been shown in many developing countries that the best way to improve your economy is to give women more money. Here's a couple of studies to get you started. It makes no sense to keep 50% of the population explicitly in underpaid roles.