Does My Airport Extreme Handle Bandwidth Better than a Netgear?

This may be a random question. Please forgive my long set-up. (I'm somewhat ignorat when it comes to wi-fi.)

The wi-fi at my in-laws is extremely slow. I've checked with their Internet provider and they seem to have a fast connection. (I've also tested it with speedtest.net and it was fast on their hard-wired computer.) They have a cheap NetGear wireless router and I'm thinking this maybe the problem. My guess is that whenever multiple devices are connected to the wi-fi (like, when people come over for the holidays), the router simply divies up the bandwidth equally. In other words, if they're getting 18MB/s and we have 9 devices that are connected to the wi-fi, each device is getting 2MB/s. That obviously becomes a problem when we want to use more bandwidth on one or two of the devices (like watching a movie) while the other devices just need minor bandwidth (for checking mail or reading a webpage).

Here are my questions: Could that possibly be the case with that cheap NetGear router? And, if so, would replacing it with an old Airport Extreme I have help resolve that problem?

Here are the rest of the details: The Airport Extreme I have is Model Number A1143 (I don't know how to tell if it's a MA073LL/A or MB053LL/A). And, unfortunately, I don't know the model number on the NetGear wi-fi router.

Thanks!