I found the same re: compressed stream, however I also found that hand optimizing the decompressed JSON made for significant performance improvements on underpowered devices (e.g. some old Android phone).
In general text formats are a compromise. They are bulky and and inefficient to parse. What you get in exchange is ease of development.
If you are willing to complicate the format just to improve performance, at some point you no longer get ease of development and you should just switch to binary altogether.