So, as you can see, it's not really to the obvious benefit of cable companies to work with third-party add-on devices like the TiVo. But it's also unlikely to be purposeful sabotage. It's far more likely to be the result of sloppy engineering on the part of those engineering the set-top boxes used by cable providers. As the "adorkable" ZeoTiVo stated in the TiVo Community Forum:

Far more likely is just engineers doing what is easiest in their cable box design versus being talented enough to take third party concerns into account. Cable boxes are meant to be low cost as cable companies use them in volume and you never see a cable company touting their cable box as being the best out there.

There is simply no design incentive to make a Cadillac of cable boxes or pay extra to ensure a function does not interfere with a small subset of customers.

And interfere, they do.

And yet, it's actually in the cable companies' best interests to actively support TiVo and other add-on DVR customers -- if they would only realize that TiVo users are a customer base rich in opportunity. You see, the typical, non-DVR user is likely to watch only the TV he or she is actually physically present to see. Purchasing the high-cost programming packages with all the premium channels often makes little sense, since that customer might only be around to watch TV from 7pm to 10pm each night.

But the typical TiVo customer scours all the channels and can record anything playing at any time, watching it when convenient. As a result, the typical TiVo customer will likely purchase all or most of the premium channels, because every program out there is readily available for later viewing.

Although I know of no such study thus far, it's likely that most TiVo users spend two to three times more per month on cable programming services than the average cable customer. Even if the cable company doesn't get the DVR revenue, the added programming packages purchased will more than make up for the cost, and will likely net the typical cable company a much larger profit.

And yet, TiVo customers are treated as more nuisance than profit center, which is a shame. But with an attitude adjustment on the part of the cable companies, this customer base could be a goldmine.

Breakages and workarounds
I asked members of the TiVo Community Forum to report on any problems they had with providers breaking TiVos and other third party devices. Beyond the breakage I described above, one example was provided by DancnDude, who reported:

My parents have AT&T U-verse. U-verse put a feature into their box that causes it to turn off after six hours of no activity, and this cannot be disabled (my dad called and asked -- they said there was no way to shut that off). This essentially makes it hard for TiVo to record, since it will try to change the channel when it's ready to record something but the U-verse box might be off and you essentially get a recording of a blank screen telling you to turn on the box.

The only solution is to set up a series of TiVo recordings every few hours so it activates the U-verse box and will be good for another 6 hours. I told them to set up TiVo to record 10-15 minutes of the Weather Channel or news every 5 1/2 hours, so it would keep changing the channel.