I dun think they were “given” a monopoly, they were just the first to go into the e-commerce space, but this first mover advantage is now mostly gone, e-commerce is just a low margin business now, even Amazon struggles to make money from e-commerce, their main cash cow is really AWS, it has been this way for years now.
Back in the glory days Alibaba had their fingers in several high growth sectors like fintech and cloud, but this is not the case anymore, ANT has pretty much been confiscated, cloud growth has been very slow due to geopolitics. This is just a melting ice cube unless they can find new avenues of growth.