I'd love for you to expand on this.
At the end of the day, the job of a coach is to put his team in the best position to win and win a lot. These are the coaches in the sports I am familiar with who have most succeeded in winning a tremendous amount. I ask myself, if I was an owner and could pick any coach in the history of the sport who would I want? These are the guys I would choose. And I heavily lean towards the modern era, free agency and the explosion of competitive balance have made building and maintaining teams and talent so much more difficult that I think the modern guys are all heads and shoulders above the former greats.
Phil:
Has 11 titles, its a staggering number of titles. When you hire a coach their job is to win you championships and Phil did that better then anyone in the NBA. Pop is a better X-Os coach, but I actually think Phil managing to get teams that straight up hated each other or were full of crazy people to win over and over and over is just as much a part of coaching as Pops X-Os. And Phil did it in what IMHO was the best era of talent in NBA history from the early 90s to early 2000s. Pop winning five in the modern era probably puts him number 2 on the NBA list.
Scotty Bowman:
I'm just gonna quote his wikipedia page. His achievements actually exceed Phil. He is the greatest coach in history and is some sort of hockey talent savant. "As head coach, Bowman has won a record nine Stanley Cups; five with the Canadiens (1973, 1976, 1977, 1978, and 1979), one with the Penguins (1992) and three with the Red Wings (1997, 1998, and 2002). He has also won five Stanley Cups as a member of an organization's front office. He was director of player development for the 1991 Penguins, Consultant with the 2008 Detroit Red Wings, and Senior Advisor of Hockey Operations for the 2010, 2013, and 2015 Chicago Blackhawks. Bowman won the Jack Adams Award in 1977 and 1996. In the 1976–77 season he won a record 60 games, breaking his own record of 58 wins the year before. He broke his own record again in the 1995–1996 season, with 62 wins. His 8 losses in 1976–77 are a modern record. His teams also made it to the Stanley Cup Finals a record 13 times and the semi-finals a record 16 times." Wanna win a Stanley Cup? Involve Scotty in your org in some shape or form. He is in his mid 80s and still helping the Hawks win cups.
Nick Saban:
College football, you get one loss, but its better to be perfect. To be a successful college coach you not only have to be a great XO's guy, but you also have to be able to build and develop your talent. Saban has done this at two schools. Something no one else has done and he's won five national titles in a sport that is more competitive now and being played at a level of skill that far surpasses its previous decades. And he is still at his absolute peak of coaching with no reason to expect him to not break Bear Bryant's record. And he is getting better, he showed flexibility as a coach in this years title game he has never really shown before in his coaching history. He has dominated a sport in a way that shouldn't be possible with how college football is setup and all he does is keep winning.
Bill Belichick:
A literal football genius who has won superbowl after superbowl in a free agency and parity driven league with a run of excellence with the Pats that just doesn't exist in the modern NFL. This a sport where the majority of the time the Superbowl loser doesn't even make the playoffs the following year or losing your QB means you go 1 -15. And the Pats have been the most consistent team in the league for 15 years. And he was a great assistant coach in the 80s and 90s. Posting his resume from Wikipedia: If you can win like this in free agency era of the NFL you are a special coach.
"6× Super Bowl champion (XXI, XXV, XXXVI, XXXVIII, XXXIX, XLIX)
7× AFC champion (1996, 2001, 2003, 2004, 2007, 2011, 2014)
2× NFC champion (1986, 1990)"
Coach K:
Built and maintained the most successful college basketball program of the modern era in a sport that is radically changed in the time he has been coaching and he is still winning titles. Winning the NCCA tourney is so difficult that making the Final Four is celebrated as much as actually winning the entire thing and he has won five titles in three decades and has 12 final four appearances. He will build you a better, more sustainable program then any other college coach in history and he can handle it in the midst of the implosion that was college basketball for a long time. He also dominates someone like Tom Izzo who is maybe the best XOs coach in modern college basketball and wins Gold Medals coaching Olympic teams and FIBA teams.