If you’re not already aware, take a look at tree pod burial, depending on country/states.
for example, look at https://www.greenmatters.com/p/tree-pod-burials
this article from the same site lists the availability in different states in US: https://www.greenmatters.com/sustainable-living/what-states-allow-green-burials
On a note on matlab, in addition to industry, there are certain fields in academia, eg neuroscience and many engineer fields, where matlab has been part of their culture for quite some time. My guess is you can make the case for some other proprietary softwares used in university. Changing culture in a field is not an easy thing; but fortunately people in science usually notice these issues and make a choice for themselves.
Plus, like you said, it’s used in industry, eg matlab in engineering and adobe in design. One argument one could make for university paying for proprietary software is that they get their students ready for the jobs in industry afterwards. So the teaching needs to be with these softwares. Of course, it would be preferable if they also offer education with the alternatives in the same course so that students can be more adaptable. But that can many times add more workload to already complicated concepts for the students to learn.
Plus, the world is larger and more complex than what it used to be. Whether we like it or not, offloading tasks to other entities, rather than completely doing everything by oneself, is usually the preferred solution, especially if the cost of implementation/adoption is high and those other entities have experience with such issues. The example is email, like the other commenter explained.
So, I think the universities see the needs for these proprietary softwares, either because the complexity is too high (eg email, per the other comment), or (some of) their faculty/students want it (eg matlab, adobe).
Thus, I don’t believe the answer is complete rejection. It should be that universities give people at least a choice in the matter, where possible; for instance, matlab and the alternative is python or julia. This is evident in HPC setup where they offer many packages rather than forcing students to settle with only proprietary stuff. And they should also advocate more open source and free alternatives; and usually university libraries do this.