> why are we worried about Kessler Syndrome with the thousands of satellites and junk that is already up there?
One, Kessler syndrome should really be called the Kessler hypothesis since we’ve never actually proven it’s a problem in any real form. To the degree it’s been rigorously modelled, it would create a lot of property destruction in a limited number of orbital planes, not block access to space. The problem is breaking stuff. Not blocking. Two, where it’s been rigorously modelled and shown to be a problem (again, only for a limited set of planes) it derives from something big breaking apart. Not lots of small stuff. And again, we’re talking about a bunch of property destruction. Not annihilation of everything in the plane let alone orbit.
First, no one's really talking about Kessler syndrome and cascades except you, though they make any denial effects bigger.
Second, take the volume of the entire shell around earth from 400km to 450km up-- that's about 3 * 10^19 cubic meters. 1.3 million objects scattered randomly over this entire volume yields a density of 4 * 10^-14 / m^3, which sounds like a small amount, until you consider that a moderate sized object orbiting at that altitude might sweep 20000 m^3/second. You'd expect this indiscriminate attack on LEO from a single launch to hit 2.5% of objects with this 2.5 m^2 cross-section in the year that the BBs stayed in orbit. You'd expect to hit the ISS about once every 2 hours and to accrue hundreds or thousands of hits.
To the extent that you focused your attack on certain planes and on a narrower range of altitudes, you could expect it to be more effective. And, of course, to the extent that there's any further fragments created / Kessler-type effects, you can expect more effect.
One, Kessler syndrome should really be called the Kessler hypothesis since we’ve never actually proven it’s a problem in any real form. To the degree it’s been rigorously modelled, it would create a lot of property destruction in a limited number of orbital planes, not block access to space. The problem is breaking stuff. Not blocking. Two, where it’s been rigorously modelled and shown to be a problem (again, only for a limited set of planes) it derives from something big breaking apart. Not lots of small stuff. And again, we’re talking about a bunch of property destruction. Not annihilation of everything in the plane let alone orbit.