As to be expected whenever you live in a poor realm. A Byzantine Empire that survives in the Middle East would be much wealthier realm with larger and more well developed cities, which could easily create the kind of middle classes that pursue intellectual development. As it was, the Byzantines were quite poor. Urban centers in Anatolia and the Balkans drastically shrunk as food supplies from Syria and Egypt dried up, with Arab raids causing further economic destruction.
But we know what a Byzantine Empire possessing the wealth of Syria and Egypt could and did do, and the efflorescence we see under the Arabs is simply lacking.
As a further point, although it's about as cliche as anything else, many leading Byzantine scholars have pointed out the dearth of sources. It's possible Byzantine intellectuals came up with various concepts at similar times to their Muslim rivals, and probably received knowledge from them from the Muslims themselves at any rate.
We have plenty of Byzantine works; the idea that we're missing some corpus on the scale of the early Islamic intellectual tradition because they were all burned seems a bit farfetched.