A division will ariseth...
There will be those for whom blogging and podcasting will remain a much-loved hobby. And there will be those whose income stream and business branding requires them to podcast and blog.
But the vast majority of those currently blogging and, especially, podcasting, will find the amount of time and energy required to blog and podcast too much.
Their ROI will be insufficient to justify the demands in light of competing demands such as sleeping, eating, spending time with the family, earning money to pay bills, etc., etc.
I know that there is an increasingly large amount of tumbleweed blowing through blogspace; no doubt courageous, witty and resource-intensive podcasts will start to fall by the wayside shortly as their creators run out of steam (creative, financial and time).