They are indeed hurting their business for short term profits. Due to a number of robocalls I receive, I decided to ignore and block all calls from landline numbers. 99% of landline call I receive, are from robocalls these days. If someone wants to call me with a landline number, they must inform me first and I will store their number on my phone.
In my country, landlines starts with certain code. So I simply ignore and block any number that starts with those code. I hate robocalls. I wish there was a way to reject all calls coming from numbers who aren't on my contact list.
My phone is always on silent. Unless I am expecting a very important call. I prefer not to be notified. I am even tempted to invest some time and write an app that does exactly what I want -> Reject all calls from unknown numbers.