How can I get executives to prioritize and invest in the channel?

What will executives invest in? Things that produce a good return. You need to be able to demonstrate that the channel will produce superior results to the direct team. If you have a track record to point to, use that. If not, perhaps you can use a competitor’s track record of direct vs. indirect sales. Or, you can show how many partners you need to recruit having an average of X salespeople who have an average of X customers who buy X dollars per year. Be sure to include a cost estimate for partner management, training, and support. The channel is very easy to justify from a financial standpoint.