I thik its definitely true n the first generation. This is most likely due to the anime, seeing as bulbasaur and squirtle never evolved, while charmeleon had a grand total of three episodes
In Johto, this was just the same, though Bayleef got quite a bit of screen time, Croconaw was only seen in the intro to Pokemon 4ever and Quilava appeared in one episode, I think.
When we got to Hoenn, things improved a bit. With all three starters evolving at leat once, we got to see plenty of Grovyle, Combusken and Marshtomp. Plus, these threee were all kick-ass characters who got some episodes devoted to them, meaning they got more publicity.
So far in Sinnoh, things are looking good for 2nd stage starters. Moferno is looking like a distinct possibility, and Kenny as a recurring rival has his Prinplup. Plus, we've got Grotle too.