Perhaps my response was a tad blunt...
> try a fix public IP address with a "wrong" not matching reverse dns address without having an SPF record for the domain
No argument with this bit - as I found out the hard way - stuff wasn't even going into spam folders, it was being silently disappeared after being 'accepted for delivery'. This still happens in some places, and for 'reject' you are effectively not entirely wrong if the recipient has a vast overflowing spam folder and doesn't have time to look.
There's too much money in the spam-processing business, it's tied too closely with malware and therefore the money in the virus processing industry, and as long as 99% of people don't know the true scale of it, there's not enough interest in picking up the task of killing something that big.