> …people routinely modified the system classes. People! What can be done? — reject libraries that change system classes? — accept that library version G is

> …people routinely modified the system classes. People! What can be done? — reject libraries that change system classes? — accept that library version G is said to work with system version F, and may not work with system version Q? — accept that along with library source code comes the burden of resolving library conflicts?