DevOps is not the "application of the development processes to operations tasks". There are a few different takes on what DevOps is, but I describe it as a mindset or culture where the deployment, operations, and maintenance of a system is considered throughout the SDLC.
The idea of "DevTest" or "DevQA" already exist. It's called Agile, as defined by the Manifesto for Agile Software Development and the Twelve Principles Behind the Agile Manifesto. Although the Agile Manifesto isn't the only way to break down silos in an organization, it is probably one of the most common.
To understand this, you'd have to step back in time. In the days when plan-driven models were seen as the way to build software, you would have silos. Depending on the organizations, the silos would be different, but would often be based on the phases of the SDLC - you'd have a requirements team that turned stakeholder needs into a specification, an architecture and design team that turned the requirements into a design specification, a coding team that would take the design specification and turn it into code, a test team that would take the built product and test it, and then a release or operations team that would take the system and deploy it and run it.
But this wasn't efficient. The idea of "throwing work over the wall" to the next team just led to communication delays, rework, and other waste and slowness in the development cycle. The various Agile methods realized this and sought to tear down the walls of product development and called for cross-functional teams - nearly all of the agile processes (XP, Scrum, Disciplined Agile Delivery and so on) call for a cross-functional team that contains all of the knowledge and experience needed to deliver working software on a regular basis.
However, in the early days of what would become the Agile methods (the late 1980s and 1990s), operations was different than it is today. Advances in virtualization, containerization, infrastructure as code (and the ability to more readily manage the configuration of infrastructure), and cloud computing changed how operations tasks could be done. These advances and changes led to the ability to tear down the silos between the product development organization (business and product, development, test, quality assurance) and the operations team.
Going back to the Agile Manifesto and the principles behind it, a few of the principles would be a little different in a DevOps culture:
Business people, developers, and operations staff must work together daily throughout the project.
Working software and the infrastructure it runs on is the primary measure of progress.
The best architectures, requirements, and designs, and infrastructures emerge from self-organizing teams.
The way that this manifests would depend on the development organization. It may be a continued operations team that is involved with ongoing development as a form of a specialist role. It could mean that operations experts are put on each team to support the team's activities. It could also mean that one or more members of the development teams have some level of cross-training in operations work. Or it could be a combination of these.