The reason I specified large software companies, is that support and customization works well up to a certain scale, but won't give you a "big five" size company. A software Mittelstand which profits from support and customization might indeed be a possible future, but I think is far from a certainty. Also, I wouldn't consider that to be without disadvantages.
Two example disadvantages:
1) As it is, support and customization for specific non-technical paying users are among the things many top engineers least like to do. The reason being that it takes away from time solving the problems of the large mass of non-paying users. Even under the support & customization model versus the proprietary model, the number of paying users is much smaller in the first case in general, which creates a smaller "high priority" class of users.
2) Certain features and applications, such as traffic-aware maps or voice recognition engines are easy to build by huge centralized organizations which hold all the necessary data. They are challenging things to implement for loose collectives of smaller software companies, specially in a privacy-aware way.