Just the data and code needed to make the “algo” scale to what it is means there is no good way to “open it up”.
But let’s say, and why not, that it actually was opened.
I can see it now, everyone and their mother would be recommending changes to it. People would want it at the extremes, or tweaked to just not recommend their pet peeves.
And if they did not get their way, they would go off in a huff and threaten to join another service.
Years ago I ran a big enough service that had millions and millions of users every month. A member of the military came on and demanded we allow him to do something that was against TOS.
He complained that this was what he fought in Iraq for. So he could write anything he wanted anywhere.
America is certainly not free and it’s time we stop giving our content to services like Twitter and Facebook if we believe that.