I think Australia after winning the World Cup has become a formidable team they win against any team in the wolrd. Their outstanding performance in the Test matches against Pakistan demonstrates their batting power and helps them secure victories. Australian team balanced strength in both batting and bowling, the upcoming series against the West Indies appears promising and beat him if consistency played like against recently test series. Australia is set to qualify for the World Test Championship as long as they maintain their dominance and win against west Indies.
It is only natural that the team with the best 4-day domestic cricket setup in the world (Sheffield Shield) is dominating test cricket. County cricket of England and Plunkett Shield of New Zealand comes next, but they rank lower. Quality of Ranji Trophy cricket in India has seen some improvement in recent times, but the problem is that there are too many teams taking part (38 in total) and the national players almost never participate in these matches. For example, Bhuvneshwar Kumar recently played a match for Uttar Pradesh, after a long gap of 6 years.
Of course, Australia is going to be the best team in test cricket because they have the best setup in domestic cricket. But I think this is going to matter less and less in the future. Especially because shorter formats of cricketers getting more and more popular. I already do not think that just cricket should be a thing in this day and age. But for some reason, ICC believes that it is going to be good to keep test cricket alive. But nothing is as long as just cricket is alive, having a good domestic setup is going to be great for every test-playing nation. And Australia is doing that the best.