So what if parkrun numbers drop? Those that want a timed run can enter a race and put some money back into the sport. Or they can look at their own watch.
There used to be a lot of club organised 5k races. They brought a lot of money into the sport. Parkrun killed them.
They cannot compete with the zero cost of parkrun entry, which parkrun only manages because it is technically not a race and therefore there are no licensing/venue hire costs.
park-run should be a mass run - that is how it exists in the licensing world. Races are the competitive events, whether that is competing with others, or competing with your own times.