Microsoft's behaviour was publically blamed for Be Inc's failure - not least because that gave more weight to Be's case against them - but in reality they were merely one of many factors. The main reason Be failed were Be themselves.
I partly agree with this but I mainly blame Microsoft.
Many of Be's decisions were forced on them:
Hobbit to PowerPC because the Hobbit was canned.
PowerPC to x86 because Apple killed the Mac clones and wouldn't give them details of Apple hardware.
They did begin to get interest from serious 3rd party developers from the Audio industry and could have taken over that market but for the focus shift.
The focus shift happened because they couldn't make money on PCs, by not getting the OS to a wide audience they couldn't get developers, by not getting developers they couldn't get more users.
If Microsoft had not forbidden companies to dual boot BeOS would have shipped on many systems - even Dell were said to be interested, everything else would have followed from there.
But by not getting users in the PC world they ended up going after the IA market instead because there was no other way to make money. That killed the Audio companies interest and the rest is history.
I do think they made the mistake of only concentrating on the technology, they should have made a "solution" becuase that's ultimately what sells. Unfortunately in the Tech industry this is a very common mistake and one notably Microsoft have not made.