The issues are mostly in the SME segment and where it really depends on what your business is. Do you need completely separate system for each customer? In that case, AWS is going to be easier and probably cheaper. Are you running a constant low 24/7? Then you should consider buying your own servers.
It's really hard to apply a blanket conclusion to all industries, in regards to cloud cost and whether or not it's worth it. My criticism in regards to opting for cloud is that people want all the benefits of the cloud, but not use any of the features, because that would lock them into e.g. AWS. If you're using AWS as a virtual machine platform only, there's always going to be cheaper (and maybe better) options.