This guy was incredibly lucky in finding a mostly non-corrupted floppy available for sale. In just a few years the few remaining working floppy originals will cease working and MacApp will end up as just another lost piece of software - unless pirate copies are made.
You can say and think what you want about software piracy, but it's undeniable that it has saved a lot of ancient software and games from ceasing to exist in anything other than our memories. Illegal software/ROM archives have probably done more to keep the revolutionary time of the early computing/gaming history alive than all the legal old-fashioned libraries have done combined.
http://www.pcworld.com/article/248571/why_history_needs_soft...
Thankfully there is very little enforcement of the copyright law on ancient software - and so few developers/publishers are bothered enough by the fact that someone is illegally enjoying, archiving and sharing their 10-30 year old software that they bother issuing takedown notices - that it is effectively "legal", or at least tolerated in the same way as cannabis is in the Netherlands. The fact that it won't actually be really legal until 2040-2060 is totally absurd, and a powerful testament to how outdated and irrelevant the current copyright laws are.