Embark on a comprehensive exploration of revenue trends witnessed by Walmart Inc. over the past three fiscal years, spanning from January 1, 20X1, to December 31, 20X3. With revenue figures of $500 billion, $550 billion, and $600 billion for each respective year, discern the trajectory of Walmart's revenue growth and elucidate underlying drivers catalyzing or impeding its expansion. Employ analytical tools and methodologies to dissect revenue streams across geographies, business segments, and product categories, unraveling key insights into Walmart's revenue diversification strategies and market penetration initiatives. Furthermore, juxtapose revenue performance against industry benchmarks and peer group dynamics, facilitating a nuanced understanding of Walmart's competitive positioning and growth trajectory in the retail landscape.