[exDM69]

In the article, two specific bands of altitudes are mentioned: "orbital junk in two bands of LEO space—the 900 to 1,000km (620 miles) and 1,500km (930 miles) altitudes—already exceeded the necessary density."

There is hardly any atmospheric drag at these altitudes. The ISS is (and Mir and Skylab were) only half of that altitude and even that would survive for years before naturally re-entering due to orbital decay from atmospheric drag.

The problem of orbital debris will not sort it self out given enough time. It is already a hazard to manned spaceflight as well as satellite operations.