philo wrote:

Now that you brought this up I see maybe my "good deal" was not so good
as I've paid $70 this year to rent it...and I bet I can get one on eBay
for that price.

You don't even have to go used. You can get a new DOCSIS 3 modem for
about that price. My observation is that cable modems last a long time.
My TWC-supplied Motorola lasted for more than ten years, until they
started charging rent and I bought my own.

ISPs do indeed recover their costs in less than a year of modem rental
fees. After that, the modem generates pure gravy for them until a system
technology upgrade or something else other than hardware failure forces
a replacement.