Indeed, and there will absolutely be a “real” slim version, probably in the next year or so. The existing case is massive and mostly empty— so it’s really a matter of getting the thermals under control, whether via a better airflow design or by die size reduction and therefore power/heat savings at the source.
Well, and just the history, that literally every prior generation of PlayStation had one or more eventual size-reduced versions come out, though the time gap is clearly shrinking:
PSX launch was 1994, PSone in 2000.
PS2 launch was 2000, slim in 2004.
PS3 launch was 2006, slim in 2009, super slim in 2012.
PS4 launch was 2013, slim + pro in 2016.
It's interesting to see them roll out power-reduction die shrinks on the launch chassis— presumably they'll be able to monitor telemetry on these units over time and that'll allow them to build confidence on moving into a chassis with a drastically-reduced size and weight footprint.
Given that the PS5 launched in late 2020, it's not unreasonable to expect a PS5 slim for the 2023 holiday season.