Up until a couple of months ago I'd owned two excellent E61 machines. An HX, ECM Technika Profi IV and then a double boiler Profitec Pro 700. I recently moved to a Linea Mini and the really significant difference (in my opinion) is the steam pressure. The LM runs its steam boiler at 2 bar, both E61 machines maxed out at 1.2 bar. I'm wondering why higher pressure steam boilers aren't installed in prosumer level machines that are less costly than the Linea Mini? I'm guessing that for an HX that it might be difficult to tune the heat exchanger to be short enough given how hot the boiler would be. I'm confused however as to why 2 bar steam boilers aren't standard fare in the upper range of the E61 double boiler market?

Cost? Energy consumption?

Cost - possibly, although the Linea Mini isn't ridiculously more expensive than an E61 DB.

Energy consumption... higher temp/steam pressure can be dialed down if the owner is worried about this issue.