There were definitely problems and abuses with the model.

But the hardware itself was robust and reliable.

Remember: "We don’t care. We don’t have to. We’re the Phone Company"

Fake commercial on Saturday Night Season 2 Episode 1.

(It wasn't called Saturday Night Live until later.)

I find the story of Walter Shaw Sr. even more instructive.

Independent inventor convicted and gaoled by AT&T for "misdemeanor attachment", the crime of attaching non-AT&T equipment to AT&T's phone network.

https://en.wikipedia.org/wiki/Walter_L._Shaw

More on this in the first bit of "The Inventor and the Thief" on Snap Judgement:

https://www.wnycstudios.org/podcasts/snapjudgment/episodes/l...

Because the hardware didn't do much of anything!

Contrast Minitel, a videotext online system provided by the French government phone monopoly Postes, Télégraphes et Téléphones in 1980.

https://en.wikipedia.org/wiki/Minitel

See also the Charter lawsuit where it was revealed that Charter was renting very old equipment to their customers for years and didn't care.

That's where the minimum standards aspect comes in. The problem of noncompetitive monopolies failing to innovate and actively quashing independent inventors (see: Walter Shaw, Sr., amongst many others) is a risk of this approach.

AT&T didn't just come out and install a newer telephone because they had a newer model. If the equipment is fit for the service why replace it?

If you rent a $100 device at $10 a month for 10 years you end up paying $1200 and still not owning it.

I can see why consumers and consumer advocate groups don’t like this.

The customer should always have the option to buy their own hardware - that's to me something that was fought for (and won) with Carterphone

Sorry, I managed to reply to the wrong comment.

AT&T later in its history, 1960s - 1970s, offered the option of uplines (touch-tone, "Streamline", "Princess", and eventually Mickey Mouse telephones) as service upgrades. So there wasn't no interest in innovation, though I'd agree with the general view that the interest was low.

None of those were real technical improvements over the 500/2500 set however, they were upgrades designed to please the customer aesthetically.

Meaning, all of those sets performed more or less (in some cases less, specifically in certain special service applications) identically to a 2500/500, and at least one of those was a 2500 in a mouse shaped box.

Touch-Tone was actually a value add for the telco because it reduced register holding times in crossbar switches, and could reduce the amount of common control hardware needed, yet they still charged more for it (and the service too)

(Also, I think you mean trimline not streamline)

Thanks, yes, Trimline.

I'm really not going to try to defend AT&T's specific level of innovation.

I'm noting, however, that the possibility of offering a range of hardware at a range of price levels and allowing for volitional subscriber updates is possible, and was practiced.

I should have said they were renting very old and inadequate equipment; it wasn't fine and they knew it.