Remember, PIMS were a hot market prior to Windows 3.0 - but most products were never ported to Windows because there wasn't enough revenue being made. This was because users would buy the hype, buy the product but weren't commited enough to get past the learning curve and dedicate time to maintaining data in it. So, most PIMs just became shelf-ware. And it wasn't because they weren't powerful or didn't have good interfaces - they did (as Grandview and Agenda easily demonstrate).