I think there are a couple of different things getting mixed together here.
It is completely reasonable to ask questions about pupil numbers and finances at the moment. I would certainly want to understand those things before choosing a school. But I also think there is a danger in taking bits of information and turning them into fairly definite conclusions when we don't necessarily know the full picture. With schools that can become a bit unintentionally self-fulfilling too, because confidence affects applications and pupil numbers.
I'm also not sure that joining a bigger group is necessarily the obvious solution. It may work very well in some cases, but Royal and Longacre are recent examples where being part of a much larger organisation didn't ultimately guarantee the future of the individual school. Bigger may bring advantages, but it doesn't automatically mean safer, or that what made a school distinctive will remain.
More generally, and thinking about themes from some of the other threads, I sometimes think these discussions become far too focused on pupil numbers and GCSE/A-level percentages as though they tell you whether a school is good or not. Pupil numbers in particular aren't necessarily a proxy for the quality of the education, and for some children a smaller school or a more individual environment may actually be part of the attraction.
I've interviewed plenty of extremely high-achieving students over the years, including students predicted three, four or five A*s, who are fantastic at answering an exam question but really struggle when you ask them to think creatively about something they haven't been explicitly taught. Equally, some of the most impressive students aren't necessarily the ones with the most perfect set of grades or from the very "top" schools. Results clearly matter, but they are still quite a crude measure of an education.
One of the things I actually like about this area is that the schools are different. Some are very academic and selective, some are particularly strong creatively, some in sport, some are very good at building confidence or supporting children who might not thrive elsewhere, and most will have strengths across several areas. A school doesn't have to look like the biggest or most selective option to be exactly the right environment for a particular child.
I don't think it would be a good outcome if a difficult market gradually reduced that diversity to a smaller number of schools all trying to offer essentially the same thing.
For anyone actually choosing a school, I would look at the finances and ask questions, but I would definitely go and see the schools, ask those questions in person, and not make decisions for or against based only on what is being inferred online. Meet the pupils and staff, understand what each school is particularly good at and think about where your own child is most likely to thrive and make the most of their abilities.
We are fortunate to have such a varied group of schools in this area, each offering something slightly different, and hopefully that diversity persists well into the future.