When we want to express the idea of something happening or being present in a vast or substantial manner, we often use the phrase "great extent." However, there are many other synonyms that can help us communicate the same idea in various contexts. For instance, we might use words like "enormous," "immense," "extensive," or "considerable" to depict the magnitude or scope of something. Additionally, we can use terms like "far-reaching," "deep-seated," or "profound" to convey the idea that something has a significant or meaningful impact or influence. Ultimately, the appropriate synonym for "great extent" will depend on the specific context in which it is used.