Antonyms for the phrase 'to great extent' could include 'to a small degree', 'to a limited extent', or 'minimally'. These terms suggest a lack of intensity or a lesser degree of impact or influence. Other antonyms might include 'inadequate', 'unimportant', or 'insignificant', which would indicate that the extent is not sufficient or relevant to the situation at hand. Additionally, 'not largely', 'to an insignificant degree', or 'to a minor extent' might be considered antonyms which suggest a lack of significance or importance. Overall, these antonyms suggest a degree of limitation, restriction, or minimized impact, as opposed to a substantial or significant extent.