strategy + business on the future of enterprise software by Mitch Rosenbleeth, Corrie DeCamp, and Stephen Chen:
The Coming Software Shakeup
"Five years ago, 11 companies controlled 90 percent of the database market; now only six do. In business applications, the trend is even more pronounced: Seventy percent of the market is now controlled by just 35 companies, compared with more than 120 companies in 2000.
About 25 percent of software is already sold by subscription; that’s likely to increase to more than 50 percent in the next four years. This approach will also speed acceptance of “software as a service,” which lets customers access programs via the Web and pay only for the amount of time that they use the software."