Unless it is 1 device wifi hotspot to 10 users. If speed test is showing 5Mbps, it means it is given 5Mbps/device, so it does not matter more people or not, there is enough bandwidth for that particular area for that particular no. of users right?IMHO.
Let's say 10 users need to watch Youtube at 5 Mbps. You need 5 Mbps or 50 Mbps ?