Let's examine your math. So this year there were 86,000 visas for 2017 that last for 3 years. So that means by 2020, if the visa limit stays at 86,000, there will be 258,000 H1Bs, of course this assumes that H1Bs were created in 2017, we are ignoring all those that came before. Let's NOT ignore those and look at the below link -
http://insights.dice.com/2013/05/14/how-nearly-800000-h-1b-w...
Yes, in 2013, it was 775,957. So by now, let's say it's closer to 1.2 million. That's a third of all software developers in the USA.
So Yes! This is exactly the reason that American wages are depressed in the job markets that H1Bs work in.