Just not worth it to be spammed with ads. 

So have access to private lending sources as well as banks. hope this doesn't seem like spam.

If you called but did not leave a message, maybe he thought your call was SPAM, and maybe your email went to his junk/spam folder. 

I'm wondering if my numbers are bad, or people just aren't picking up the phone with all the spam going on.

Said every spam email like that.

Craigslist is overrun with spam and since their revenue model is low, they have no money to hire moderators.

Instead of marketing (I call it spam) to a bunch of buyers who you don't have that criteria for, you can identify exactly what they want.I use to do this all the time, but there are easier ways of getting buyers without asking a single question and know what they want to buy, how much they would pay, their financing etc... 

See here: FCC to require phone carriers to authenticate calls by 2021If you use something like Callrail for tracking purposes and use their numbers for cold calling they are now showing up as "Spam Risk" on caller ID which has dropped the contact rate significantly.

When I get cold calls now from "investors" it's marked spam call on my caller ID. 

If you even touch their ad you will get spammed more than you ever have in your life.