The mobile app development industry in the USA was thriving and experiencing significant growth. It is essential to note that the industry is highly dynamic and subject to continuous changes and advancements. Therefore, some of the information provided here might have evolved since then.

Here are some key aspects of the mobile app development industry in the USA:

1. **Rapid Growth**: The mobile app development industry in the USA has been growing rapidly, driven by increasing smartphone adoption and the popularity of mobile applications among businesses and consumers alike.

2. **Tech Hubs**: Several cities in the USA are renowned tech hubs and centers for mobile app development, such as Silicon Valley in California, Seattle in Washington, Austin in Texas, and the Greater Boston area in Massachusetts. These regions attract top talent, startups, and established tech companies.

3. **Diverse Applications**: Mobile app development spans across various sectors, including finance, healthcare, e-commerce, entertainment, education, transportation, and more. Businesses from almost every industry are leveraging mobile apps to reach and engage with their target audience effectively.

4. **Startups and Innovation**: The USA's mobile app development industry fosters a culture of innovation, which has given rise to numerous startups working on groundbreaking app concepts. Venture capital funding and incubators support many of these startups, driving the creation of innovative solutions.

5. **Competition**: With the growth of the industry, competition among app developers and development companies has intensified. This has led to a focus on delivering high-quality apps, cost-effectiveness, and efficient development processes.

6. **Enterprise Mobility**: Businesses have increasingly embraced enterprise mobility, creating custom mobile apps to streamline internal operations, enhance productivity, and provide better services to their customers.

7. **Cross-Platform Development**: Developers have been exploring cross-platform development frameworks to build apps that can run on multiple operating systems, reducing development time and costs.

8. **AR/VR and IoT Integration**: Mobile apps are incorporating augmented reality (AR), virtual reality (VR), and Internet of Things (IoT) technologies to offer immersive experiences and connect with smart devices.

9. **Data Security and Privacy**: With the growing concern about data security and user privacy, mobile app developers have been investing more in secure coding practices and compliance with relevant regulations like GDPR and CCPA.

10. **User Experience**: User experience (UX) has become a crucial factor in mobile app success. Developers are increasingly focusing on creating intuitive, user-friendly interfaces to ensure app usability and retention.

Overall, the mobile app development industry in the USA has been dynamic and promising, catering to diverse industries and user needs. It remains an essential driver of technological innovation and economic growth in the country. However, it's important to research more recent sources to get the latest information on the current state of the industry as of 2023.