Right you really are on most of this.
You cite imitation, derivation, improvement and tribute as the way that progress is made, in the arts and sciences. I actually advocate that.
But in the instance of Microsoft as a company, there are endless back-room rip-offs, double crosses and secret handshakes. They extend from (at least) QDOS through VMS and VINES to SGI (Rick Belluzzo, look closely) - right to the present day: Nokia and Win7 stink to heaven. This was a weird deal in the back room, if ever their were one.
Nokia is essentially a subsidiary of MS, without the legal tripwires. They ditched a successful if future challenged business, to sell devices by the folks behind Zune and Kin.
I know of at least TWO Sr. Execs at MS, who were dismissed because of flagrant sexual harassment, who each went to "penitence" jobs at minor MS partners, only to surface 6-9 months later in Sr Exec jobs at Nokia - where their function relates to Microsoft, corollary partner to their former roles.
Gates stole BASIC, in the beginning. Everything thereafter followed this pattern.