That’s largely as a result of its branding strategy (single brand, only two mass-market models). There are 19 production vehicles based on VW’s MEB platform, say, most of them very similar. This is fairly typical; all of the big car manufacturers have at least a couple of brands, and many models, and some (notably VW, Stellantis, GM) have _dozens_ of brands, largely with shared platforms.
A lot of that is selling just 2 mass-market models. And it only barely beats out the Toyota Corolla, except that Toyota also sells the third highest volume model (the RAV-4) and the 8th (the Camry).
But when you add up sales for all models from each company, there are 12 companies that sell more cars each year. Market share is 11.07% Toyota, 6.41% VW, 4.87% Honda, 4.82% Ford, 4.56% Hyundai, 3.84% Nissan, 3.77% Suzuki, 3.53% Kia, 3.48% Chevrolet, 3.47% BYD, 2.67% Mercedes-Benz, then 2.77% for Audi and Tesla, and bringing up the rear of the top 15 is 1.85% for Renault
Yet, Tesla makes more profit than most. It's like saying Apple has no market-fit vs Android because it's far less popular… until you realize it's a strategic choice to sell fewer vehicles but at higher margins.
Tesla hasn't started going down market with cheaper cars. But they've said new, cheaper models will be released by June 2025. We'll see what happens for the cheaper and higher-volume segment of the auto market.
But for now, Tesla has the most popular model with the highest margins.