You're forgetting game 6 Klay is next.OK?
Steph/Klay combining to go 12/27 (44%) isn't crazy, although 27 attempts between them is significantly higher than any other game this series.
The rest of the warriors combining to go 8/15 (53%) isn't remotely sustainable. Even excluding Durants 3/3 it's still 5/12 which is above the rest of the team's average considering basically everyone else is a mid 30s 3 shooter. The non-Curry/Klay Warriors have averaged above 40% 3s in only 5 out of 21 games and 3 of those were with a fully healthy Durant who not only helps those numbers but also opens up a lot of room for others, also they were against teams whose defense isn't as good as the Raps.