Efficiency of Jitsi network

Dear all,
We deploy jitsi on our proper servers for serving the conference of about 35 participants. I already paid attention to the bandwidth of each participant by constraining the BW in the config.js as the following:
constraints: {
video: {
aspectRatio: 16 / 9,
height: {
ideal: 320,
max: 320,
min: 180
However with the real measurement, a JVB serving 3 rooms like that consumes already about 120Mbps as in the snapshot

My question is then if we would like to serve 100 rooms of 35 participants we will need about 30 JVB with dedicated 120Mbps bandwidth. It is a real investment for infrastructure. Or I can further tune-in the system for better efficiency ?
Many thanks