This article is about the "AI chips" Nvidia makes that undergird the major cloud services though, not the cloud services themselves. So I think it's a hardware issue, more akin to a monopoly of GPU or CPU markets? Especially since Nvidia's competitors in most spaces seem to be limited to AMD and sometimes Intel.

I can certainly imagine Nvidia having anticompetitive practices with their hardware and/or the software for their hardware, as they have done so many times with GPUs, though this particular article really doesn't go into any detail.

Honestly micro lithography and chip design in and of themselves have been moving towards only a few big players in the space. TSMC is more advanced than any other manufacturer, and NVIDIA’s chip designs at the top end just have no competition for raw performance and capability, even aside from their software/AI work. Don’t get me wrong, all the major chip manufacturers have their respective anticompetitive bullshit, but traditional silicon is such a hard space to even keep up in, never mind break into.