The horizon of private tutoring is rapidly transforming due to the advent of technology and changes in socio-economic dynamics. The evolutionary trajectory of this industry is likely to redefine the concepts of learning and knowledge delivery in the coming years. By understanding these shifting trends and future predictions, stakeholders in this sector can prepare to adapt and thrive in the changing landscape.

Private tutoring, or shadow education as it's often called, refers to instruction provided outside of the formal education system by specialized tutors. Unlike traditional classroom learning, it offers personalized attention, customized learning techniques, and flexible schedules. In recent years, this industry has witnessed exponential growth, driven by competitive academic environments and increased parental investment in their children's education. These factors are expected to continue propelling the demand for private tutoring services.

However, the industry is not impervious to changes brought about by technological advancements and socio-economic factors. The metamorphosis on the horizon is largely typified by digitization, democratization, and diversification of private tutoring services.

The advent of technology is perhaps the most potent force shaping the future of private tutoring. In this context, the rise of digital platforms plays a quintessential role. Online tutoring platforms leverage cutting-edge technologies such as artificial intelligence (AI), machine learning, and data analytics to provide personalized, real-time, and interactive learning experiences. They offer the benefits of traditional tutoring, such as personalization and discipline, while adding the convenience of remote access, flexible scheduling, and access to a broader array of subject matter expertise.

However, these digital platforms also come with their trade-offs. For instance, while they offer accessibility and convenience, they may lack the personal touch and relationship-building aspect inherent to traditional face-to-face tutoring. Furthermore, they require reliable internet access and digital literacy, which may leave behind those in lower socio-economic strata or technologically under-served regions.

The democratization of education is another significant trend shaping the future of private tutoring. As the socioeconomic disparities widen and cost of education rises, there is a growing need to make quality education and tutoring affordable and accessible to all. Thus, solutions like group tutoring, sliding scale pricing, or community-funded programs are expected to gain traction. These trends could redefine the market dynamics from an 'elite' service to an accessible tool for many, thereby driving market expansion.

The third trend is the diversification of offerings. As the knowledge economy evolves, so do the skills and competencies required. This has led to an increasingly diverse demand for tutoring in areas beyond traditional academic subjects, such as coding, entrepreneurship, or soft skills. The ability of private tutors to offer specializations in these niche areas could play a vital role in determining their future relevance and competitiveness.

Despite these shifts, it is important to recognize that the future of private tutoring will not be a one-size-fits-all scenario. Cultural, regional, and individual differences will continue to play a critical role in shaping demand and delivery mechanisms. For instance, in societies with a deep-seated culture of rote learning, perhaps the adoption of technology and non-traditional subjects may be slower. However, with continued globalization and homogenization of education systems, these differences may be gradually ironed out.

In conclusion, the future of private tutoring is likely to be a complex interplay of traditional and novel forces. While technology, democratization, and diversification are set to redefine the industry, inherent nuances and individual variations will continue to shape its evolution. By understanding these trends and being agile in their response, private tutors can continue to make significant contributions to the learning journeys of their students.