BIM Building Design software: open source versus closed ?

BIM and IFC: an opportunity for new innovative players (open source type) to enter the Building design software environment market OR a strengthening of the major players position? (closed source type?)
BIM, Building Information Modeling: the concept
IFC, Industry Foundation Classes: the standard

High Performance Buildings

above picture from US National Institute of Building Science

The question is: In order to improve building performance, the building market is today requesting more collaboration between the different building disciplines and especially at the design phase.
The proposed answer at software level is a concept BIM + a standard IFC:
BIM (Building Information Modelling): the process of generating and managing building data during its life cycle at the software level.
IFC(Industry Foundation Classes) the associated  standardization led by BuildingSMART (International Alliance for Interoperability) aims at insuring software inter operability.
the design software impacted are: (see picture below)

• dealing with architecture, civil engineering, structure engineering, mechanical, electrical, plumbing
• from a 3D design, schedule, pricing, analysis& simulation point of view

BIM Building design software concept

Who are the players today on the market?

• The major players:  Autodesk, Bentley, Netmetsheck propose a comprehensive BIM software offer covering all the building disciplines (sometime with partnership with other software providers such as Dialux for lighting design). There is a high inter operability between the software products of their own range. This communication capability goes beyond what is today supported by IFC, and especially in areas where IFC standardization is today weak such as Electrical. This allows them to bring to their users all the benefits of BIM.

• On the opposite, other players propose software which are focused on one discipline(Example: CLIMAWIN in France focused on thermal calculation). They offer IFC import/export to communicate with other software . So their communication capability with other software is at the level of IFC definition and so poor in some domain

My conclusion so far,  is that these 2 scenarios are equally probable for the coming years:

• IFC standardization can’t reach a satisfying level and the building market request of more collaboration between the software players is going to strengthen the major players position (because they are the only one to be able to propose a comprehensive offer).
• IFC standardization succeed and anyone can propose added value software on a limited perimeter but able to interface efficiently with any other IFC software. This will be an opportunity for new innovative players to enter the market.