Why aren’t laws such as putting to death idolaters, homosexuals, and adulterers still in place? Especially in Israel. And will they ever be in place again?

Firstly, even in Biblical times, it was very rare to actually give the death penalty, and the Torah's threat is mainly a deterrent. Secondly, the same God Who gave us the Torah, is also the One Who runs history, and He knows that at this stage, such punishments will do more harm than good. Today's Israel is part of the democratic world, and religion is based upon observing mitzvot out of identification and not just out of force or peer pressure. Apparently, today, God prefers this more positive type of observance.