よりほかない・
These expressions state that circumstances leave no available course except the action named. They are most natural in writing or deliberate speech, especially when presenting a reasoned conclusion.
Reaching a no-alternative conclusion
The preceding context normally shows why the other choices are unavailable. The action immediately before より is the only course left, not one side of an ordinary comparison.
Written-style reasoning
資金援助が得られない以上、計画を縮小するよりほかない。
Since financial assistance cannot be obtained, there is no alternative but to scale back the plan.
AnalyzeThe opening clause removes the possibility of continuing the plan at its current scale.
The difference between the two variants
よりほかない presents the conclusion in a relatively detached way. より仕方がない can sound more resigned because it suggests that no workable method or solution remains. The difference is a tendency, not a strict rule.
Careful spoken use
修理用の部品は、もう生産されていないそうです。
Apparently, the replacement parts are no longer being manufactured.
Analyzeそれなら、新しい機械に買い替えるより仕方がないですね。
In that case, it seems we have no choice but to replace it with a new machine.
AnalyzeThe expression is possible in speech, but the measured workplace discussion supports its deliberate tone.
More examples
主要道路が閉鎖されているため、海岸沿いの道を迂回するよりほかない。
Because the main road is closed, there is no alternative but to take the coastal detour.
Analyze現時点では証拠が不十分なので、調査を続けるより仕方がない。
Since the evidence is insufficient at present, we have no choice but to continue the investigation.
Analyze締め切りの延長も増員も認められないなら、作業範囲を見直すよりほかない。
If neither an extension nor additional staff will be approved, there is no alternative but to reconsider the scope of the work.
Analyze双方だけでは合意できない以上、第三者の判断に委ねるより仕方がない。
Since the two sides cannot reach an agreement by themselves, there is no choice but to leave the decision to a third party.
Analyze原本が失われた今、残された写しから文書を復元するよりほかない。
Now that the original has been lost, there is no alternative but to reconstruct the document from the surviving copies.
Analyze天候が回復するまで、ここで待つより仕方がない。
Until the weather improves, we have no choice but to wait here.
Analyze