Except this is Trump, and he's president of the US. The call to Zolensky was monitored because it was an official call, and all calls of any official capacity are monitored.
As for the Sondland call, if Trump is talking that loud that anyone can hear him, that's his own fault, NOT the fault of other people. And if people asked the person involved in that phone call for clarification, and it is clarified, again, NOT their fault.
Of course Trump will still be in the White House, because the Senate, when it gets that far, would never hold Trump Accountable for anything he does. The ONLY way the Senate would verdict him guilty and remove him from office is if there is so much proof that Trump acted not in Accordance with his office that the public outcry and risks against loss in the election would force them to vote against Trump. That's not likely to happen however, and the Republicans don't honestly care if Trump is guilty or not. They won't care about evidence, all they'll care about is keeping their guy in office as long as possible.
As for wondering how it happened - nah, not a wonder at all. Trump did this to himself.