Memory's pretty hazy here, so someone correct me where I'm wrong
One of the major deficiencies in Apple's OS at the time was lack of real multi user capabilities; like Windows pre XP. NeXT, coming from BSD, had this built in but BeOS was pretty much a single user OS
As well as Multiprocessor support, cooperative memory management AKA lack of OS controlled memory management and a host of other issues. Remember OS7 shared lineage from the original OS1, some sins that they hacked to make it work back then, where hard to remove after the fact. While they where technical marvels at the time (1984) they became handcuffs later on.
I have (fond?) memories of using Get Info on various applications and setting how much memory they would take from the OS, and then going to About This Macintosh to check how much memory I had left over.
Incidentally, up until version 7.6, the Mac OS was simply called "System", as in "System 6" and "System 7". (Systems 1-5 were rapidly iterated through and forgotten--even System 6 still ran on a Mac Plus). Mac OS 7.6 was the first version that was designed to run on clones, hence the change from generic "System" to "Mac OS".
One of the major deficiencies in Apple's OS at the time was lack of real multi user capabilities; like Windows pre XP. NeXT, coming from BSD, had this built in but BeOS was pretty much a single user OS