"Testers are the gatekeepers of quality"
Let’s be clear software testers are NOT the gatekeepers of quality. They don’t control or limit access to quality software or services.
Testers investigate, observe, and report on their findings. Some may go further to fix bugs or build systems to detect problems. They work with developers, product managers, and other stakeholders to ensure the product or service meets the customers needs. Do they control or limit access to low-quality software? No.
People can be gatekeepers. Release managers or anyone deploying code quite literally have control. Teams in high trust environments have some control over decisions, testers included. Decisions making power is important for our agency. It can also give us the false sense of control when it is overridden by someone with more authority.
Gatekeepers can also be laws, mechanisms or systems. Feature flags, feature rollouts and deployment pipelines can limit access to low quality software. (This assumes you know what changes or decisions might reduce quality in advance.)
The assumption that testers are the gatekeepers of quality is misguided. Testers play an important role in assessing quality, but the control is not theirs.
The Association for Software Testing is crowd-sourcing a book, Navigating the World as a Context-Driven Tester, which aims to provide responses to common questions and statements about testing from a context-driven perspective.