Nothing more than anecdotal evidence, when I last looked into the externally available network details on a number of low-budget VPS hosting companies...   I would say that if anything, a person who really knows what they're doing operating a properly MX, will face more difficulties today than they did 3, 5 or 7 years ago operating the system in the same netblocks as IPs which have been previously abused.

For obvious reasons the IP reputation systems and antispam tools at the biggest destinations (gsuite/gmail, office365, etc) are treated as closely guarded proprietary data.

My personal theory on a whole /24 acquiring a poor reputation, is that it does have some correlation with the density of random $5/mo VPS customers and the turnover of different customers between the same small group of IPs. And exactly how many misconfigured smtp sources have existed in that block within some previous range of time, how much spam has been reported/flagged, etc.