Some are saying Guest Posting aren't going to work?

[ksmith29]

If you publish your blog posts in a place where real people comes and real people writes genuine content. Then it won't matter you will get the link juice alright.

Exactly correct. People have been spamming since the birth of the internet and this industry but guest blogging has been always there and will be present in the future. If you provide information to place where people come looking for it then it will always be helpful.