The industry is changing towards more automated testing, I heard of a lot of AAA studios implementing/creating testing frameworks. It was very uncommon back in the days, they just threw a bunch of badly paid and overworked QAs at new builds. Games are very complex, covering a wide range of behaviours in environments with a lot of randomness is difficult. With automation, the predictable behaviours (for example, testing that climbing a ladder works) can be offloaded from QA and they can focus on finding more random issues with playthroughs. I guess there was also a push from engineers without a gaming background (and being more used to TDD) that have been recruited in the industry throughout the years.