If the Sabres do it right, they just rotate players around their core. Tampa and Chicago were masters of this method.
Chicago: Toews, Kane, Keith, Seabrook, Sharp, Hossa, Hjalmarsson
Tampa: Hedman, Stamkos, Kucherov (with Palat, Johnson, Killorn, Paquette on the roster). Vasilevskiy was on the roster but wasn't the stater in 2015.
Chicago moved on from Versteeg, Brouwer, Ladd, Byfuglien, Bolland, and Campbell. They added in Saad, Shaw, Leddy, Kruger, Oduya, and Richards. And they changed goalies from Niemi to Crawford.
Tampa had the big three on their first Cup run when they lost to the Blackhawks. They moved on from Callahan, Stralman, Drouin, Namestnikov, Connolly, Sustr, Nesterov, Gadas, and Bishop. They elevated Vasilevskiy as a starter, traded Drouin for Sergachev, and added Point, Cirelli, Gourde, Verhaeghe, Cernak, McDonagh, Rutta, Goodrow, Colton, and Coleman.
Buffalo has a core and enough organizational assets to shuffle players out via trades when they become unaffordable and replace via trade or player development. Completely possible with the depth in the organization they have.