True, but you can increase PhoneNet bandwidth by using a star controller. A well designed star configuration on a fast back bone will deliver the entire 230Kbps LocalTalk rate to all attached devices. We used this method up to mid 1995 to run a small lab of SEs. It was fine for running small apps like Word 5.1 and Excel 4 from a file server.
A bit of network history that you might appreciate:
http://www.net.cmu.edu/docs/arch/article2.html