Why hypersonic missiles are unlikely to replace submarine torpedoes

Will submarines shift toward VLS-launched hypersonic missiles as their primary weapon, with torpedoes secondary?

Probably not for crewed hunter-killers. Hypersonic missiles could supplement their weapons, while dedicated missile or autonomous arsenal submarines could make greater use of them.

A hypersonic missile launch produces acoustic, thermal and electromagnetic signatures that expose a submarine's position. Hunter-killers depend on remaining concealed while attacking, which makes torpedoes a better fit for their usual role. Hypersonic weapons could become an additional submarine capability without becoming the primary armament of crewed hunter-killers. Dedicated SSGNs and autonomous or optionally crewed arsenal boats offer possible exceptions because their main purpose could be missile strikes. Even for land attack, hypersonic weapons are expensive and have much less routing flexibility than Tomahawk: a missile travelling at Mach 7 still needs a large turning circle. A surface combatant can perform many of the same missile missions more cheaply, reducing the case for assigning them to a submarine.