The blame game
I think Zen have done themselves no good at all with this 'announcement'.
First of all, and any ISP should know this all too well, depending on BT engineer's 'tests' is courting commercial suicide. I had the experience of complaining for nearly two years that a certain line, which was poor at the best of times, became near unusable (voice and data) during and after wet weather. It took them THAT long to discover that a cabinet in that infamous 'last mile' was flooding and had standing water in it!
Secondly, I'm not too sure the chip is to blame either. I'm responsible for three Netgear DG834N units, which initially were fine, around the beginning of the year one started dropping with increasing frequency (Zen), another dropped occasionally (Demon) and the last, my personal unit (Zen), was stable - AND the furthest from the exchange...
As the year wore on things got worse, but only for the Zen connections (the Demon DG834N issues resolved themselves when the telephone cable finally broke and lay pathetically huddled in the street - something even a BT engineer had to admit was a fault),
Even mine started dropping a couple of times a week, the other became nearly unusable.
After a few calls to Zen, always courteously dealt with by English speaking staff in the UK - but with no resolution of the issue, I decided to dig a bit deeper. Logs and error messages suggested DNS issues.
Eventually I decided, after much unsuccessful experimentation, to go OpenDNS - and like magic, all was fixed.
Now I'm not going to state that Zen's DNS provision leaves more than a little to be desired, but my experience was that removing it from the equation resulted in a complete cessation of issues.
Ah, you say, but, you are talking about DNS issues, the issue here is 'loss of connection'. Well that's a very loose term. What exactly are they talking about I wonder? The 'connected' 'link light' going out? Or 'the internet isn't there any more'?
DNS failures of the type I've observed, and suffered myself, are certainly a 'loss of connection' to all intents and purposes. And easily confused with an ADSL connection or sync failure.
Zen's problem is that their announcement makes it sound as though they are passing the buck. And from my limited experience, that my be the case. Not a smart move when you are one of the most expensive ISPs in the country.