a) It takes time. Existing companies are huge mammoth like structures with supply chains that extend across the globe, so change happens a step at a time. Positive changes have been made since Rana Plaza, some people say not fast enough, but remember because so many parties involved things can't happen over night.
b) Systemic change has to happen and for this to occur, collaboration is needed. And when I mean collaboration, I mean with EVERYONE who is part of the system, including the authorities. Take for example, a few stores setting up a clothes recycling bins is only a small step, but collaborating with the local authorities to have an official collection .... now that's big impact and everyone can get involved. If you are looking for alternative technologies to recycle mixed textile blends or a create a waterless dye, why not work together with other brands to develop it so you get economies of scale when it comes onto the market. It's a win-win for the brands and the environment.
And then there is this .... the vast amount of information on the internet .... there is so much that people jump to conclusions and they don't dig deeper. If in doubt, try searching for the information yourself, treat what you see that gets posted or shared with a pinch of salt.