if they wish to increase the number and the amount of donations made they need to change a number of things.
They should make the option to donate more prominent.
They need to offer clear options for specific donations. In other words the option to donate per episode or a donation for a specific goal. For instance an event they wish to organize, bandwidth, whatever... People will donate more if they have a good idea of what will happen with their money. If there was a clear breakdown of goals (travel, website costs, podcast costs, etc) you could choose to donate to a specific goal or to the general budget. it would also be possible to track % of funding achieved needed for an episode/year/month/goal.
Steve needs to mention the possibility of donating every single episode. He needs to ask explicitly for the donations and he needs to do so regularly. This will be more effective if he states clearly how a little can help a lot. $5 buys us.... $10 buys us.. etc.
it is clear that they are not that interested in the fundraising part and want to spend more time on the skepticism. For obvious reasons. However, they would achieve a lot more if they had more cash...