Really good question Justin. I guess my instinct would be not to try and sell the full thing all at once. I would start by maybe trying to do one or two quick activities and see if they help.
The Affinity Map is a good candidate. It is pretty flexible and can be finished in an hour or 2. Most managers can usually find 2 hours to try something new. If that goes well, then next time you could suggest conducting a little research before the Affinity Mapping and then slowly build from there.
That being said, some businesses are pretty opposed to change.
One other quick thought regarding the c-suite executives specifically. They are usually very open to hearing about ‘cost saving’ measures. What I would do is try and find a few examples where development time was wasted because the team hadn't done enough planning or research.
If you can find just 1 to 3 days worth of development time that could have been saved you have a small research budget ($1000~)to try out.
I’d be interested to know what you think would work or any specific objections that come up.