Trendy Trees (the merits of untrendy trees)

There are trees which have fallen out of foul of current trends.  Likewise there are some trees that are so ubiquitous that  they are often specified without taking into account the planting location.  Betula utilis var Jaquemontii (especially multistem), Pyrus calleryana Chanticleer,  Photinia fraserii Red Robin in my view, fall into this category, whilst they all have many plus points, doesn't the frequency of planting reduce this?  

Even where these ubiquitous trees are planted, don't  specifiers have an obligation to plant a wider range of trees? Are they being lazy just recommending the same trees over and over for different sites.

Tree Nurseries are always introducing new trees and new varieties of existing trees.  Whilst I acknowledge that these trees are often suited to; a warming climate,  planting in relatively restricted areas or clones that do not fruit, the nurseries after all that investment will push these trees, without the   knowledge of the specific planting locations possessed by the planter. 

A prime example of a group of trees that have fallen out of favour are Lawson Conifers.  These have a variety of forms and foliage colours. In addition they are relatively slow growing compared to other similar Conifers and mature at smaller sizes.  

We appreciate that if there is not demand from specifiers, growers will be less likely to invest in un-trendy trees,  due to a combination of cost and risk of not selling them, but how do we break this cycle?     Even is there a need to break this cycle?