Yes, but this is where there is understanding required. After the holy prophet Muhammad (SAW) passed on and his holy body was laid in the maqam it is now in and he (SAW) is alive there … The Sahabah, most likely stopped asking directly from him (SAW) and started asking from his (SAW) close relatives (RA) to do the du’as for them on their behalf.
The way to make du’as is and always has been directly to Allah (SWT). Even durood is to Allah (SWT) … If you want to speak directly to those in the grave there is nothing wrong in sending them Salam … As is the case in Salat … Where we send RasoolAllah (SAW) Salam.
There are 3 different things here … There is a difference between asking someone to do du’as for us, from asking Allah (SWT) to grant us our du’as by using the name of the loved ones of Allah, and asking from the loved ones of Allah directly … The first two are present in hadith … I am not aware of the third type to be present in hadith … I could be mistaken.