The existing system was designed to accommodate two groups, but also to accommodate a society where there was students in abundance, and there was always more children than parents. The inherent duplication of effort that happens in any parallel system always has higher costs, but as long as the system keeps growing every year, no one cares.  Now, it's not, it's shrinking, and quite frankly, it's never going to stop shrinking.

Right now, there's a board here and a board there where Catholic schools are out soliciting for public students to pad up their totals. Fast forward 20 years and every Catholic board in the country will be in this situation, and most Catholic boards will be on the edge of closure.

All this ruling does is speed up the inevitable, or more accurately, stop the Catholic boards from engaging in a long, slow, costly rear guard action as they fade from public life.