The opposite. The S-400 is very important for the sole reason that it won't allow recon aircraft to peak into an area defended by the SAM.
150-250Km is the sweet spot for recon aircraft. They have to travel further in to spy on ground units, 50-100Km. So you can imagine what the S-400 can do to these aircraft.
If we get enough S-400s, like the IAF wants 10-12 regiments, not just 5, then the entire airspace can be protected. Then the sole purpose of the other SAMs, like Akash, SPYDER and MRSAM, would be to protect the S-400, while the S-400 protects everything else.