Data communications over telegraph circuits 1906
First, in this discussion we must be clear whether we're discussing pre- or post- divesture AT&T. Pre-divesture "Bell System" is probably a better name since it was one company that generally was consistent throughout.
Data communications over telegraph circuits 1907
Well, you may want to reconsider. All complex systems have mbuttive failures. You may reduce the impact of them by duplicating...
Secondly, pre-divesture all AT&T could provide was what was allowed by the consent decree.
Third, within communiations services could and did provide special engineering services in many cases.
As to overall marketing, things changed drastically before, during, and after divesture. Expecting AT&T or the baby Bells to turn overnight from an engineering-oriented company to a marketing-oriented company is unfair and a double standard.
I do agree that AT&T made bad business (not marketing) decision after divesture It bought and sold some companies that had the potential of being very profitable, for example cable TV and wirelesss. Unfortunately, their base core businesses--manufacturing by Western Electric-Lucent (which they spun off) and long distance ceased to be high tech speciality work and became commodities. That is always tough for a large mature company that once had strength in technology but lost the advtg because others caught up.
It was similar in the steel industry. Building and running a steel mill once took enormous amounts of capital and business skills to find the land, raw materials, run the processes, and distribute the product. But today it's not that hard and smaller firms--who have less overhead and pay a lot less--have jumped in. Let's remember that much of AT&T and the baby Bells remain unionized while the compebreastion is not. AT&T finds itself stuck with a 1920s bldg that is no longer needed, but the building is filled with asbestos and to tear it down will cost $$$. AT&T has big pension obligations from the past. The steel industry (like the airline industry) handled all that by bankruptcy and voiding all obligations from the past. New companies don't even bother with pensions.