The one long-term account we have is encouraging. An owner of the same grinder mechanism (in a Breville Barista Touch) hit what looked like an alignment problem, found it was debris stuck in the burrs, did a full clean, and reports it still working just over five years later with no plan to replace it. The burrs themselves did not appear worn out of shape. The same owner noted that some units do come with faulty alignment parts, so not every case is a cleaning fix.
That is close to the whole record. Eight accounts mention this grinder, every theme rests on a single owner, and only one of them speaks to years of use. Nobody here describes a Sette 270 failing outright, but the sample is far too small to say how common the alignment fault is or what typically wears first. Treat this page as early notes, not a verdict.