Good DHs have long lifespans. Not at the level (or pay) he's at now of course, but J.D. Martinez was in the post-season. Cutch just re-signed with Pittsburgh. Justin Turner is 40.
But I'm not convinced Schwarbs can get that big a raise given his age. He was 29 when the Phillies signed him, and teams also know what his down years look like (not like he's going to go back to 2020, but certainly his 2023 is probably more typical going forward, a 115-120 OPS+ guy).
All depends what he does this year I guess.