Which of these two consoles do you consider to have been more successful, (in your view of the word) and in what way?

XBox Series and it's not even close since the original XBox has a somewhat subpar software lineup and not that good of a 3rd party support and no real JRPG's. The original XBox did not even sell enough for Capcom to bother porting the second Onimusha game to it even though the first game on the Xbox had a preview of the second game on the disc.

Financially? Series by far. Original Xbox lost them over 1 billion. Culture wise original Xbox wins. Halo scared Sony into making a response game and by PS3 era Sony was putting out a lot of shooters to take away from Halo. For a first console it was a pretty strong start with a good library.

OG Xbox.
It was up against the PS2 and as a newcomer and releasing last it still managed to outsell the GameCube.
It gave birth to franchises like Halo and Forza too.

Yeah, nope the four people that voted for the original XBox need to take of their nostalgia googles and I'm pretty sure they did not own both consoles.

I don't own any googles. I'd be rich if I did. I own three original Xbox's and a Series X. Maybe you should read the topic and the replies. OP states which is more successful "in your view of the word." Reading comprehension and spelling is hard isn't it.

Well, no matter how you look at it the Series is a way more successful console and again the people that voted for the original XBox need to take of their nostalgia googles.  Seeing things with Nostalgia googles in gaming is a worse problem than recency bias when talking about sports.

Probably the original Xbox. It established presence in the market, allowing for its successor to do quite well, and it also had some iconic games. Series has shrunk the market share considerably, and no wonder. The original Xbox probably didn't do too poorly regarding its objectives, wheres Series has probably done absolutely terribly. Short-term financial success is probably the only clear thing going for Series over the original - which isn't to downplay it, but that financial success doesn't really seem like it's resulting in a good future for Xbox (and to be clear, I don't know how successful Series has been financially, but it's probably better than the original Xbox's).