Re: pdp-11 ... not sold but leased until DEC lost their market
"The pdp-11 on the other hand was not sold but leased until DEC lost their market."
There may have been some companies supplying PDP11s on leases, but customers who wanted to own them could own them.
I started working with PDP11s in the late 1970s (an 11/40 with a whole 128kW of memory and around 10MB of disk, supporting half a dozen users) and it was owned not leased, as was every other PDP11 at every other user I subsequently visited.
You could also get non-DEC OSes to run on various flavours of PDP11. An early UNIX or two, for example (the obvious one plus Venturcom's Venix). The UK's Central Electicity Generating Board wrote their own OS and tools to use for real time control of power stations. Others too.
Not entirely sure what your point was. Apologies if I misread.