Also as far as rumors go - it makes literally no sense to cancel the Dopey Challenge... The addition of the 10k added a reasonably large number of non runners aspiring to do their first race... Prior to Dopey the 5k's were small and very low key. The vast majority of people I meet running the 5k's are Dopey's.
I would also take rumors of Dopey being discontinued any time soon with a grain of salt, but I think you actually highlight a
possible rationale for discontinuing it rather than Goofy.
Sales in general have been increasing over the past couple years, with other 5ks outside of Marathon Weekend selling quicker and quicker without being part of a challenge. Dopey runners are likely to run Disney races anyway -- people were running Dopey before it was officially recognized -- but the 5k and 10k races are more welcoming races to new runners and non-runners, which seems to be runDisney's niche market. Dopey sold 7,737 bibs which necessarily limits the number of individual 5k and 10k slots. That's thousands fewer individuals buying merchandise*, park tickets** and hotel reservations, not to mention thousands fewer getting hooked on the runDisney brand in the long run.
Again, I'd take the rumors with a grain of salt, but I don't think Dopey is necessarily superior in terms of financial benefits to runDisney or Disney Parks & Resorts, which clearly has a say in some of runDisney's operational decisions.
*Dopey runners eating up 5k and 10k slots means fewer people buying individual shirts and other merchandise for those events since Dopey's can cover those events
and the half/full marathons with one Dopey shirt/mug/etc.
**Remember, park tickets are less $/day the longer your stay, so there's a benefit to selling the same number of days for smaller packages. Not to mention individual 5k and 10k entrants could make a vacation of it, potentially leading to
more days being sold.