If i had to guess, i would say because they paid alot of money to Lucas Arts to use the Droid name on there devices
on top of that, they make it stand out from other carriers using the "Droid Does" or "Droid (name)" use
so far the only phone on VZ with Android to have the "with Google" branding is the Droid, which makes this phone a true google android experience, so another reason for "the next chapter in the Droid saga" is also being used
and another reason why i think its the successor to the Moto Droid
and if you look at the unique names we have in todays marketplace that stand out, for example, the Wii everyone made fun of it then it stuck
when iPod was first announced no one knew it would be a hit, now its got its own designation in stores ipod/mp3 not going by MP3 which is why customers would always ask "whats the difference between and iPod and an MP3 player?"
also another reason for the Droid name and the increased marketing over what they did for Eris is because this phone is truly the successor to the current Droid throne on VZ which is the Moto Droid, look at the marketing campaign thats being used on the website then rewind back to when Eris came out, big difference huh? I will miss the QWERTY from my TP2 but after seeing the search by Voice and landscape keyboard on screen, i'm thinking i will adapt to it
now we just need to get this thing rooted and ROM's made for it!
then i can start making my themes for Sense 2.1