Indeed, the ongoing fashion shift from locally installed software to external services is quite problematic, as it shifts the control over the user's data from the user themself to… whatever tree/graph of third parties somewhere in the network where the data is accessed, processed… and further shared (willingly or not, knowingly or not, in conformance with the agreements and laws or not) which the user has no control over.

That being said, it seems like an almost inescapable consequence of the fact that the software itself is also data and as such subject to a similar problem: in times of ubiquitous high-speed internet access where you can't protect software (data) from being widely copied and shared over the network once anyone else gets hold of it, the only simple and reliable way for a software company to keep control over the distribution of their software (and thus its monetization) is to never share it in the first place but only provide access to it as a service.

So in the end, the shift from locally installed software to remote services kinda comes down to the fact that most users don't have the same level of awareness or care about their own data and keeping control over it as the software/internet service companies have for their data (e.g. software).

SaaS has been around for a while now.