に至っても|にいたっても

1. 1Even when a situation has escalated to a serious or extreme point, the expected reaction still does not happen.Ex. 1
2. 2Even when a particular point in time or stage has been reached, something is still unfinished or unchanged.Ex. 2

A formal, written expression found in news reports, commentary and essays. The first part names an extreme or decisive situation, and the main clause states that something still did not change, often with a critical or exasperated tone. Compare 〜に至って, where the change finally does happen once that point is reached.

• 〜に至ってN1「〜に至って」simply indicates reaching that stage or moment; the following clause often takes a 'only then...' nuance but can describe other situations, and it carries no concessive meaning. It signals a belated change or realization (often with 「ようやく」「やっと」), whereas 「に至っても」 is concessive and the outcome stays the same — the two are semantically opposite and not interchangeable.
• に至ってはN1「に至っては」 is not concessive; after listing similar cases, it picks out the most extreme one, meaning 'as for..., even more so...'. It attaches only to nouns and requires the general situation to be stated first, so the two cannot be swapped.
• に至るまでN1「に至るまで」 expresses range, meaning 'from... all the way to...', including even small or extreme items (also as 「AからBに至るまで」). 「に至っても」 expresses concession — no change even at an extreme stage or critical point — so they are not interchangeable.
• といえどもN1「といえども」 concedes an identity, status, or fact: its first clause is typically a status, extreme condition, or minimum amount, and its second clause a judgment, prohibition, or obligation. 「に至っても」's first clause is a stage or point in time things have reached, and its second clause states what still hasn't changed; the two are generally not interchangeable.
• (で)すらN1「(で)すら」 highlights an extreme example, meaning 'even...', implying other cases go without saying. 「に至っても」 is concessive: things have reached an extreme stage or critical point, yet the outcome remains unchanged; the two are generally not interchangeable.
• てもN4「ても」 is a general-purpose adversative concessive that attaches to many word classes with a neutral register, covering both hypothetical and factual (already-established) concession. 「に至っても」 is limited to extreme situations or critical time points, is written-style, and often carries surprise, dissatisfaction, or reproach; replacing it with 「ても」 is grammatical but loses the sense of 'to have come to such an extent'.

Unlike 〜に至って (only when X was reached did something finally happen), に至っては (as for X, the most extreme case), and に至るまで (all the way down to X), に至っても means that even at stage X nothing changed. It is more specific than general ても, and it differs from といえども (even though someone is X) and (で)すら (even X), which concede a status or highlight an extreme item rather than a reached stage.