Comment by wahern

Yes, and in fact underassessment and smoothing assessment increases over time is the norm, AFAIU, for the current system(s), both de jure and de facto, depending on locality. But pathological underassessment and related political issues are a much bigger problem with LVT. The swings can be much bigger (especially from the perspective of a property owner that hasn't done anything), which means managing underassessment to keep taxpayers from revolting requires more discretion, something governments have difficulty doing while maintaining a sense of fairness. Even theoretical application of LVT requires significant individualized assessments which in practice require much greater discretion. Also, LVT is intended to displace most if not all other forms of taxation, so managing the stability of your budget in light of the need to smooth out assessments becomes more problematic relative to the status quo.

Some localities have tried mixed schemes, e.g. only applying LVT to commercial zones. Businesses are savvier and are more comfortable engaging with government on assessments as well as forecasting and managing swings in assessments. But that cuts both ways; in at least one municipality I studied (a town in the southwest, IIRC), this engagement turned into straight-up corruption.