The fact something is possible does not make it realistic.
The "oligarchs" don't need to steal this election because Trump has handed it to their preferred candidate.
I just learned from my bank (Bank of America) that my computer at home had been hacked into and compromised by a secret virus. I had no idea or who could have done this. The bank says probably someone in Russia but even they don't know for sure. What they do know though, is that someone was able to look at my keystrokes and be able to know my passwords. I would have to believe that Bank of America has pretty good software considering what they do yet even they can not prevent hacking to their customer's computers.
So the point I make is this. The software in a voting machine has to be vulnerable and even if its not, the makers of the software would know how to get in. Like my own situation with the bank, the voter who is the user of this software would not have to have any idea whatsoever what would be happening to whether his vote was recorded properly. Its not only possible, its probable considering the stakes IMO.
As for your second comment, I do not think the Oligarchs care how Trump behaves excepting for the fact that they have probably already laid their plans for what the end count will be. They will make sure that the end count is of a believable variance to the mean value of whatever they have convinced the public with the media they also control.