What i dont like about SaaS model is that it discriminates poor people and blocks innovation. Every SaaS is targeted to heavy users from highly developed countries. Medium tier has to provide most value, while minimal tier must be stripped from most important features, so that heavy users from developed countries wont save money choosing it.

At the end, if you are not a heavy user or from a not wealthy country you can not use SaaS.

So you have worse chances to compete with others. And you can not innovate. Because more and more tasks require having good SaaS. More and more products are only provided as Saas. You also can not buy "older" SaaS as you could buy older cheaper software.

So to sum it up as far as SaaS still is a great way to provide a lots of niche value, it discriminates people and blocks innovation.