I seldom hear about them anymore and it seems like it was once a massive problem. I would say in the late '90s and early '00s everyone was concerned about them but maybe thanks to better security measures, they are not as much of a threat?
There has actually been an alarming rise in covert activity and a cyber threat landscape dominated by stealth. Data theft, cloud breaches, and malware-free attacks are on the rise, making Trojan horses a significant concern. I am not sure why you are not hearing about them. Maybe we just don't all use the term like we once did.
I think in certain cases, they are more of a threat now than ever but in other cases, not so. A lot of people these days make use of smart phones which are not usually attacked in this manor. It really depends on the context. Using a secure cyber security system, software, or service is ALWAYS ideal to prevent such things!
They most certainly still are a threat like any other sort of malware or virus. The language around them has changed these days and there is more of a target on phones than there used to be. It is always wise to make sure you are protected against all forms of malware.