It would probably cost about 10000% more to port the games from Dreamcast or XBox to PSNow than it would earn in its lifetime.

If only it was that easy but this is Sega we are talking about. :(

Suprisingly emulation for the dreamcast is really good nowadays.. i can play the game on my android phone, even its not the strongest one out there..

psnow's server farm can (currently) only play ps3 games...

Buy a Dreamcast and you can have all the games you want to play, just like a PSP. Best consoles ever made.

Techniquely - Since its running the PS3 OS -- it can also run PS1 and PS2 games (they just haven't added any) :D. 

I can pretty much guarantee you that they are currently building out the PS4 version as we speak. x86 servers will be drastically cheaper to maintain. (They also bought all that tech from OnLive)

i'll be honest,.. i don't know why ps4 support wasn't a top priority for psnow.  i would pay for a psnow subscription that allowed me to play my ps4 library from anywhere in the world.   as a rental service for old as fuck games it is just impossible for me to care.

I could actually see them doing that. $15-25 a month for a subscription that lets you play your digital library on any enabled device. Thats like Remote Play but with an Emeral BAM!

It would also help them to nudge people away from physical.

$15-25 is a bit steep to play games i already purchased but i would totally pay $5-10.

I don't see that happening man.

For a hypothetical understanding:
Renting a PS4 for 5 years would be $400/60 = $6.67 a month (no interest or tax). The electric fee on top of that will be probably $5-10 for the average gamer. This means just for hardware + electrical costs we are already at $11.67-16.67 a month. But since its server farms instead of individual units... lets half that and say $5.84-8.35 a month. This doesn't include the salaried employees or even the licensing costs. 

If you calculate the overhead that Sony has to pay for PS Now -- $15 is kinda a steal man.