Not trying to talk shit about DmD, but I'll use it as a comparison since you did: DmD launched with Day 1. I played it a long time ago, so I don't really remember, but I'm pretty sure there wasn't much to it.
I launched with 6 characters to introduce, 3 interactive and animated sex scenes, an inventory system and a navigable world. They are fundamentally different games. TP is open ended, you are supposed to go on about your day normally and sometimes nothing interesting happens, then sometimes these interesting events pop up. Furthermore, there are actually meaningfully branching conversation trees, not just "here are three 'choices', you have to click all of them and the order doesn't matter."
All of this makes the game not only more difficult to write, but also gives the appearance of less content because it's spread out, not given to you linearly all in one big chunk.
I just checked my word count and it's more than 15,000. I not going to go word-counting other games but I'm sure that's more than other games that don't get labeled as low-content. I'm so sick of hearing about how little content sometimes I wish I had just made a simple, linear VN. With the amount of time I've put in I'd probably be finished by now.