The issue is keeping things in orbit not space exploration. Realistically going through is never going to be a problem. The worst that might happen is that you need some monitoring and manoeuverability on-board of your spacecraft but it's not insurmountable. Even near Earth, space is that big.
Staying there with a lot of debris flying around really fast that could become impossible.
_Your_ launch will be very unlikely to be hit by debris, but _one of_ the 86400 manned spaceflights per day will be hit. And now you've lost not only the 200 souls onboard but also a portion of the city that the suborbital spacecraft was on a trajectory towards as the punctured hull falls short of the landing pad.
The problem is the viability of technology we actually rely on nowadays: global positioning, weather prediction, surveillance and satellite communication. Space exploration is pretty low on the list of reasons people should worry about debris in orbit.
Every single time there is anything happening with space flight, there is at least one comment saying "We should literally solve every single problem here on Earth first before even thinking about anything related to space". This seems like a pretty shallow code for space flight should not happen, ever.
I've been wondering about the people who make these comments for a while, and your seems to follow a similar blueprint. I have some questions, maybe you can answer them.
What motivates this? Are you worried about Earth getting deprioritized? Is the perception that we must decide between tackling social problems/climate change and gratuitous space adventures? Are these comments a way of saying that humans should never venture beyond Earth or that we're just not ready yet? Even if you believe actual humans should never go to space, do you still believe we should have infrastructure there to support Earth?
What do you think falls under "the curiosity of nerds"? Isn't that all of science? Or just cosmology? Or space-based platforms?
The only scientists who can afford to work for free would have to be independently wealthy, that's not very common. I don't think there is anything wrong with charging money for work, even if you do enjoy that work. Like any kind of work, research science has its share of 9-to-5ers who don't really care, but those people have their uses, too.
> It's the ones who are always whining about how they need constant boatloads of public funding (which is supposed to be spent on public services)
The core problem is really that often public money spent on science leads to results that are privately monetized and closed off from the public who funded it. That's why I believe SciHub is such an important institution, because it makes research results accessible to the public who funded them in the first place. However, funding for space-based data gathering (such as telescopes) has generally led to publicly-available data - the same cannot be said for, say, biomedical research.
I would argue that research is a public service, as long as it doesn't get immediately spun off into patent-encumbered "university-adjacent" enterprise (which I would argue is nothing less than legalized corruption). Of course the issue becomes: how do you prioritize science funding and how do you balance it against other public services?
... and then what happens? Most of those pieces retain their location and momentum. "Blowing up a satellite" converts it into a cloud of smaller particles in the same orbit, possibly with some random spray, but this is not quite like billiard balls without friction.
Initially the particles are in roughly similar orbits to the two bodies that initially collided, but not precisely the same. Over time (exactly like billard balls without friction), those minor divergences mean they cover very wide areas.
Look up the "Gabbard diagram", which is a great way of depicting the outcome of a collision. There's a spray of different orbits, with some properties that resemble the original objects, but diverging significantly from them.
Edit: Here's an AMAZING 3d animated Gabbard diagram, that shows not only the altitude and period, but also the right ascension of each object. You can see the debris from the Fengyun booster sweeping around the whole planet, crossing the orbits of other objects: https://www.youtube.com/watch?v=ePuvJDVNJd0
Even if they did stay in the same orbit, a thousand objects in the same orbit presents a thousand times more collision risk than one object in orbit. But because the collision changes the momentum of all the objects involved, it's much worse than that -- the results end up all over, and some of them are too small to track but still large enough to do damage. Those are the ones you really have to worrry about.