As Lief points out, Australian universities did not really shift to online learning due to COVID-19. Some, particularly the regional universities, had already embraced online learning (a few have been doing it for decades). I suggest the more conservative capital city universities were doing a form of ad-hoc blended learning, but not admitting it. They provided recorded lectures and online assignment submission, while lecturers expressed mock wonder as to why students were not turning up. This was not good online learning, but it was online learning.
Distance education has been offered for 100 years for students from marginalized groups, and with the advent of the Internet over the last few decades, this continued online. There are decades of research, and how to books, and training courses on this.
The problem, I suggest, is not the availability of techniques, but providing incentives for universities and academics to use them. There is a large upfront cost in technology and training, which many institutions, and individuals are reluctant to invest in.
Universities are well aware that reputation based on research output attracts students, even though this has little to do with teaching quality (and may even detract from it). Promoting campus life has proved good marketing, even if it has noting to do with learning outcomes, and many universities see no reason to change this approach.
Individual academics know they will be promoted for research output, even if they spend most of their time teaching, and that is how they bring in the most money for the university. Until there are measures of teaching quality, and academics are rewarded for this, there will be little incentive for change. One way to do this is for universities who value quality education to develop and promote measures of it. The Webometrics World Ranking of Universities, from the Cybermetrics Lab is Spain, is a good example of how to do this.