He wasn't scared.
If he was scared he wouldn't have put up 20+ shots, forcing himself to get into rhythm. He was impatient, as he typically gets when his shot isn't falling; he tries to go for the home-run play instead of looking for a single. He's like a gambler who chases his losses, putting himself further and further in possession-debt. He thinks he can shift the momentum by hitting a 3, which more times often than not he can, but that can't be the lifeboat every time the team is drowning. There needs to be another center of offense to help carry that burden, where he doesn't feel like he has to be the one to rescue them every single time.
Folks are only fooling themselves if they don't think this shyt won't happen in the playoffs when Steph needs someone else to step up, and all that's there is Poole with his inconsistency and inexperience (who shouldn't be forced into that role in the first place), and Klay (who hasn't played in over two years).
Moves need to be made, and they need to be done sooner rather than later.