Don't get me wrong, option A is preferable to option B, which splinters the community by default. But in order for option A to work, the developer must 1) convince people to make the initial purchase 2) convince some people to spend a lot of extra money and/or convince a many people to spend a little extra money and 3) produce content that makes people want to continue to spend and play
In short, there's a need for solid EXECUTION. That's where 343i has failed. 1) the poor single player campaign, the lack of split screen, the initial lack of BTB and Forge, the lack of firefight and the skimpy MP content has dissuaded many Halo fans from making the initial purchase. 2) while req investment was initially high, the continued lack of content has been turning people away. People aren't going to invest more money in a game they aren't playing. 3) the content that 343i has produced so far has been lack luster... maps that reuse the same play spaces over and over is not the type of content that keeps people playing, or encourage people who left to return.
So while the business model has promise, 343i's poor execution will prevent the model from being successful, unless they show more effort and urgency with regards to providing FRESH, NEW, and VARIED experiences.
Seriously, had Halo5 MP launched with a fully featured MP suite AND given us quality DLC (instead of buggy forged maps, and copy and pasted dev maps), this business model would be the industry darling right now. Instead, we've got a mediocre proof of concept.