The strategy of acquiring and flipping assets had nothing to do with luck, and was executed nearly perfectly.
However, we had advantageous timing to maximize a few results (2015 draft having that kind of top-end talent, 2016 draft moving to 3 lottery picks, the timing of the Kane trade, etc.)
I think tanking to get two top picks was the plan. I also think the teardown was far more deliberate and planned for a few years of drafts prior to the final bottoming out. I think they torn down slowly to build organizational depth just prior to the final bottoming out. And I think they took some cues from the Penguins and Blackhawks.
Pittsburgh had the following players in the organization prior to bottoming out to get MAF, Malkin, Crosby, and Staal: Scuderi, Malone, Orpik, Armstrong, Talbot, and Whitney. The got Goligoski and Letang during the bottom out years. Post-bottoming out, the Pens won enough/traded enough players to contend and win a Cup, but they've never really re-stocked their pipeline that well (Maatta, Bennett, Despres, Pouliot) - mostly because I'd argue it wasn't that deep to start.
Compare to Chicago prior to the Toews / Kane drafts: Ruutu (who gets traded for Ladd), Keith, Seabrook, Crawford, Byfuglien, Bolland, Bickell, Brower, Hjalmarsson are all in the organization prior to picking Toews and Kane. After the bottoming out, Chicago adds in Kruger, Saad, Shaw, and Teravainen.
Chicago drafted better post-bottoming out, but more in quality than quantity. The Pens had double the top picks, but also started with way less in the organization. Once a team prospers, re-stocking the organization is hard enough. Rebuilding around the core gets really hard - Pittsburgh has struggled to find the pieces to surround their top centers. Chicago had three of their top 4 defensemen and a bunch of forwards, including Bolland at center, prior to ever picking Toews and Kane.
I know I missed some player transaction details along the way, but Chicago started with more organizational depth, allowing them to put more around their top forwards, and trade to keep re-stocking the team.
I think Buffalo gradually torn down the NHL roster to build organizational depth prior to bottoming out. Buffalo gradually torn down, adding picks and players along the way: Girgensons, Grigorenko, McCabe, Ristolainen, Zadorov, Compher, Bailey, Baptiste, Fasching, Larsson, and Carrier before finally bottoming out to get Eichel and Reinhart. They already had Myers, Ennis, Foligno, Armia, and Pysyk in the organization.
So prior to ever bottoming out, Buffalo's got it's #1 defender (Ristolainen), two impact two-way forwards (Girgensons and Larsson), scoring in Ennis, young power forwards in Foligno, Fasching, Baptiste, and Bailey, and defense with Pysyk and McCabe. And the trade equity to get Kane, Bogosian, O'Reilly, and Lehner.
Buffalo's cupboard is stocked more like Chicago's was than Pittsburgh's. I think the gradual decline was planned to gain organization depth prior to bottoming out, with the goal of coming out of the bottom of the league with Chicago-like organizational depth.