There are several reasons for the rise in SaaS (Software as a Service) web applications:

1. Cost: SaaS web applications often have a subscription-based pricing model, which can be more affordable for businesses than purchasing and maintaining software licenses.

2. Convenience: SaaS web applications are accessible from any device with an internet connection, making them convenient for users.

3. Scalability: SaaS web applications can be easily scaled up or down to meet the changing needs of a business.

4. Security: SaaS web applications are often hosted in the cloud, which can provide enhanced security compared to on-premises software.

5. Updates: SaaS web applications are typically updated and maintained by the provider, which can reduce the burden on businesses.

There are several future trends in SaaS web applications that are likely to continue to shape the market:

1. Increased focus on AI and machine learning: SaaS web applications are increasingly leveraging artificial intelligence and machine learning to improve user experience and automate processes.

2. Growing demand in emerging markets: As internet access becomes more widespread in emerging markets, the demand for SaaS web applications is likely to increase.

3. Increased competition: As the market for SaaS web applications continues to grow, competition is likely to increase, leading to further innovation and improvements in the industry.