That is no excuse for the software getting hacked. It is poorly developed, and that is the bottom line. If no one is working on it, it should be turned off, now it is just a flawed, insecure tool thats insecurity will be used against OSS.
Stop making excuses, and start fixing the sources.
Yes, they would be motivated to write optimized code rather than a bunch of crap. Their productivity may suffer, unless their tools were also optimized to run on these slower devices.
I normally write (or test) code in a virtual machine on an older system to make sure I force myself to think about impact to performance.
Stop making excuses, and start fixing the sources.