If the speed works for you, as the saying goes: "If it ain't broke, don't fix it..."
Related to your story: About 5 years ago, I signed up for AT&T Uverse (sounded GREAT: Fiber, man, Fiber!!!). They charged me for a new modem, which they told me I owned (but could NOT buy on my own...).
About one year ago, I was having trouble streaming, so I called them. They sent a service tech out. The service tech told me:
1. Even though I was signed up for 15 speed, since I was at the "end of the line", I could only get 12 speed (he was "leveling with me").
2. He said since the modem was old, they would replace it "FREE OF CHARGE".
3. He would change the speed to 12 (which saves money), then make some adjustments.
Well, it started working better, but guess what:
1. They started billing me with an equipment charge every month and jacked the rate.
2. I called them, complained and threatened to close my account, then it stopped for a couple of months.
3. The equipment charge of $7 per month resumed again.
I finally got a manager on the phone who claims, no, I don't own the modem. He agreed to remove the equipment charge, but my rate is $60 per month for a freagin speed of 12 (I am a household of 1, so it does the job). I will be switching to comcast at some point.