Top three picks since 2004:
2004
1. Alex Ovechkin
2. Evgeni Malkin
3. Cam Barker
2005
1. Sidney Crosby
2. Bobby Ryan
3. Jack Johnson
2006
1. Erik Johnson
2. Jordan Staal
3. Jonathan Toews
2007
1. Patrick Kane
2. James van Riemsdyk
3. Kyle Turris
2008
1. Steven Stamkos
2. Drew Doughty
3. Zach Bogosian
2009
1. John Tavares
2. Victor Hedman
3. Matt Duchene
2010
1. Taylor Hall
2. Tyler Seguin
3. Erik Gudbranson
2011
1. Ryan Nugent-Hopkins
2. Gabriel Landeskog
3. Jonathan Huberdeau
2012
1. Nail Yakupov
2. Ryan Murray
3. Alex Galchenyuk
2013
1. Nathan MacKinnon
2. Aleksander Barkov
3. Jonathan Drouin
2014
1. Aaron Ekblad
2. Sam Reinhart
3. Leon Draisaitl
2015
1. Connor McDavid
2. Jack Eichel
3. Dylan Strome
2016
1. Auston Matthews
2. Patrik Laine
3. Pierre-Luc Dubois
2017
1. Nico Hischier
2. Nolan Patrick
3. Miro Heiskanen
2018
1. Rasmus Dahlin
2. Andrei Svechnikov
3. Jesperi Kotkaniemi
2019
1. Jack Hughes
2. Kaapo Kakko
3. Kirby Dach
In most cases, there's been a considerable drop off after the top two selections, in some rare cases the third pick has been better than the second (or first) selections, like Jonathan Toews going third in 2006, Huberdeau in 2011, and Draisaitl in 2014.
It's also worth noting that a good chunk of first and second overall picks still remain with their original clubs, whereas a majority of the third round picks have been moved.
Any fan suggesting the team trade down hasn't done their research.