Whilst I agree with some of your other assertions about the greater purchase cost of hybrids rarely being recouped, I feel you're being too dismissive with this statement.
Reducing localised pollution is a very worthy cause. It has a direct negative impact on peoples' health, particularly in terms of respiratory illnesses. Children growing up in areas with significant air pollution can have their educational development stunted by as much as the equivalent of a whole school year. Yes, that is a 'think of the children' argument, but it is one that deserves better than to be dismissed as something which private vehicle users can't affect just because there are HGVs still on the roads, especially as HGVs are rarely found driving around housing estates or idling outside schools. A plug-in hybrid can drive around such areas emitting nothing, not to mention making a lot less noise than a clattering diesel!
I can't yet afford an EV that has sufficient range to meet my needs. By choosing a plug-in hybrid as a stepping stone to EV ownership, I am able over the next few years to make a small contribution to the health and well-being of others in the immediate vicinity of my car. It may cost me more in depreciation, but that's a price I am more than willing to pay.