I would not attack "content marketing" with repeated posts. It is a difficult topic to rank for and the sites that you will be competing against are very strong. There are tons of sites competing.
I would not attack "content marketing" with a big comprehensive page but for other less competitive subjects I would attack with a big comprehensive page if I can beat the other content that is already out there. Don't waste your time with the big comprehensive page if you can't beat the quality of the content that already exists.
.... Now... about KW cannibalization....
Saturating a market niche with content works well in tiny niches with naive competitors. You can have three pages from one domain on the first page of the SERPs - each presenting different content to read or different products for sale. Saturating a market niche doesn't work well if multiple big brands are your competitors. It's too hard to produce two or three pages on the same topic that are good enough to earn the first page of the SERPs. (Lots of people think that KW cannibalization is bad because you are "eating your own"... but in my view you are "eating your competitors" with same-keyword content. :|) <-- that pipe is a bone in the nose. Kick them out of profitable SERPs by loading the top three positions with your own pages.
So, making the decision to produce multiple pages of content for the same keyword or keyword niche should not be guided by generic advice. You must consider the niche, the strength of sites in the niche, the amount of content already out there in that niche, your ability to compete with the quality of the content already in the niche. Being able to make money from the traffic that you do get is the crux move that determines profitability and the only reason to do this other than vanity or proselytization. The people giving generic advice about this topic (or just about any topic) are blathering.
(My post above discusses keyword cannibalization on a single domain that you control. See Rand's Whiteboard Friday from last week and on August 28. He does not mention "keyword cannibalization" in those videos (putting up multiple pages about the same topic), but, in my view, it is doing it through the use of multiple domains that other people control. Often they are very strong or very popular domains that earn your content visibility or authority.)
Other recommended activities for cannibals between early May and late October.