The locals never liked the idea of changing Route 128 to I-95. Not only did it not 'sound right' to them, but it also doesn't do as good of a job of differentiating the 128-belt from other sections of highway in eastern MA. What I mean by that is that I-95 also runs from the RI border to former 128, then follows most (but not all) of 128 up to Peabody, then continues on a different roadway up to the NH border at Salisbury.
To make matters worse, I-95 SOUTH magically becomes I-93 NORTH in Canton, MA, while you're still (in reality) traveling southeast, then east. Very confusing to the average driver who always knew this roadway as "128". And, clearly, a solution that was a 'forced fit' which never actually fit.
Yes, I get it: the former proposal for I-95 to be constructed through Canton/Milton/Mattapan was never going to happen, so a section of MA 128 needed to be badged as I-95 to keep the roadway continuous. And the southern end should never have been badged as I-93, which is then marked with the opposite cardinal direction as the I-95 portion was. To the average commuter, that smacks of idiocy.
You all need to remember that Boston is a metropolitan area of steady habits. People there - despite their progressive political proclivities - are VERY resistant to change. In this case, I don't blame them. When you say '128', people know what you mean. Even weather reports refer to it (as in: snow outside of 128) and let's not forget the "128 technology corridor" that is even familiar to techies in Palo Alto and Austin. Face it, this is a much deeper concept than mere MassHighway badging. To this day, few in the area refer to the roadway as I-95, unless they just moved in from Atlanta. To the natives, it will always be 128. And that's why traffic reporters call it that. Because everyone knows what they mean.
And, it still makes a lot more sense than the damn "blue route" near Philly - which is truly meaningless.