Australia’s property markets, page-123

Back in the early 90's (if my memory serves) there was a niche market in central Melb/Syd for car parking spaces, and those that bought then have done very well - although Covid has dented things somewhat, given the changing work dynamic, which now seems to have morphed into a hybrid of 50/50 work from home X work at office. Whether this dynamic continues remains to be seen, but some evidence suggests that better productivity and employer cost savings lend itself to this paradigm shift, meaning a lesser demand/necessity for car parking spaces. It is also of note that the sector has been corporatized to a large degree (see Wilsons).
There are two other elements to the equation to consider, going forward. The first is that the new generation in the metro areas don't see car ownership in the same way we Baby Boomers did/do. To some extent they see the fulltime cost as prohibitive and cumbersome when they can rent a car for special trips. And second (in the same vein), if one looks to the nearish future of electric, self-drive cars available to rent with a click of the mobile phone, which don't require garaging, then that too will negate the need for ownership of car parking spaces.
That is not to say that the bottom will fall out of the sector, but I don't see it as an optimum investment, given the future climate expected for personal transportation and the need to house vehicles. And of course, I could always be wrong about everything, so don't let me influence your investment decisions.