While impressive, "how many satellites you can see over a major city" is not an accurate way to judge a GPS satellite network.
To understand why, you have to understand how GPS works. Basically, each GPS has a super accurate clock on board. These are all synced up. These satellites transmit a signal regularly on predetermined schedules.
Your phone or car or whatever else is using GPS listens for these signals. Your device knows when exactly all the satellites sent their signal. It listens and counts how long it takes to receive each signal. With the length of time it takes to receive each signal from each satellite, it can pinpoint your location.
For basic operations you require three satellites for an approximate location.
For precise operations you need line of sight to four satellites, as the fourth enables you to calculate your altitude.
At no point do you need more than 4 in sight.
Why this is important is because the U.S. satellite constellation has 32 currently operating GPS satellites. In addition to those, we have 8 that are currently in space, ready to turn on, but they aren't because there's no reason to have them on.
There's no doubt in my mind these satellites have additional secret reasons for being up there. That's the only reason they'd need that many.
TL;DR:While they do have more active satellites, it's pointless for navigation purposes. Additionally, counting the backup satellites the U.S. Has operational but currently turned off in "standby" mode, we still have more.
EDIT: Not everything I stated is completely accurate. See comments below for some clarifications. Make sure to upvote them if you found them helpful.