Im not sure I would agree here: from my personal experience, the increasing containerisation has definitely nudged lots of large software projects to behave better; they don’t spew so many artifacts all over the filesystem anymore, for example, and increasingly adopt environment variables for configuration.
Additionally, I think lots of projects became able to adopt better tooling faster, since the barrier to use container-based tools is lower. Just think of GitHub Actions, which suddenly enabled everyone and their mother to adopt CI pipelines. That simply wasn’t possible before, and has led to more software adopting static analysis and automated testing, I think.
This might all be true, but has this actually resulted in better software for end users? More stability, faster delivery of useful features? That is my concern.
For SaaS, I'd say it definitely improved and sped up delivery of the software from development machine to CI to production environment. How this translates to actual end users, it's totally up to the developers/DevOps/etc. of each product.
For self-hosted software, be it for business or personal use, it immensely simplified how a software package can be pulled, and run in isolated environment.
Dependency hell is avoided, and you can easily create/start/stop/delete a specific software, without affecting the rest of the host machine.
Additionally, I think lots of projects became able to adopt better tooling faster, since the barrier to use container-based tools is lower. Just think of GitHub Actions, which suddenly enabled everyone and their mother to adopt CI pipelines. That simply wasn’t possible before, and has led to more software adopting static analysis and automated testing, I think.