Probably not, but some dude in Chicago might. Cell phones are often stolen or lost. My home landline is buried up to the house and then screwed to its walls.
Oh an "expert". Here we go.
If your cell phone is lost / stolen, then one factor is lost. The other two are completely useless without it. Thus the security model is intact.
Your land line can be unburied. I used to be a phone phreaker and have tapped a few phone lines in my time. All you require is a linesman's set on copper pairs and you can make and receive calls outside the premises. If it's like the UK, you can even crack the box open down the road and tap there or just dig the lines up.
A land line is NOT secure at all. In fact it's 10x worse than a mobile phone because if your phone isn't a piece of crap you can destroy it remotely and the PIN is tarpitted so you can't get through it (caveat: don't buy an Android phone).
What's the difference between sending to a cell phone and sending to my registered PC?
1. You access your paypal account from your registered PC. That means there's not a second factor thus 2FA is pointless. You have all your credentials in one place. The point of 2FA is to separate them.
2. Pushing notifications to PCs is somewhat more difficult than mobile devices.
And finally, you are talking theory, not data. What the incidence of fake sign-ins from registered PC's or landlines v. cell phones?
No this is not theory at all. It is a security practice REQUIRED by every financial company in the EU as an example. The reason it exists is because there is data. Lots of it.
See:
https://ec.europa.eu/info/law/payment-services-psd-2-directive-eu-2015-2366_enIf you know better, that's up to you...
Edit: to note if you think you know better, when you get ripped off your bank will laugh and put the phone down on you because it's your fault not theirs so the liability is shifted (always think in terms of who is liable in financial transactions).