Are you trolling?
> Because according to their SEC filings Duolingo has pretty limited growth potential,
The global market for direct-to-consumer language learning is large, growing, and shifting online. According to HolonIQ, total consumer spend on both online and offline language learning represented a $61 billion market in 2019, and will grow to $115 billion in 2025, implying a CAGR of 11% over this period. Online language learning is the fastest-growing market segment, projected to grow from $12 billion in 2019 to $47 billion in 2025, representing a CAGR of approximately 26% over this period, and to comprise 41% of total consumer spend on language learning in 2025. We believe that growth in digital spend will be driven in part by a shift away from offline offerings, as consumers seek more affordable, convenient, and higher quality online solutions.[0]
> increasing losses (or in other words, negative gross margins)
That's not how losses and negative gross margins work. I just double checked, gross profit for DuoLingo in 2020 was 71.55% (sorry not 80%). Compare that to Mazda's abysmal 21.7%. Cars specifically require heavy R&D (which does not go into COGS), so the comparison is a nice one since R&D for DuoLingo also requires heavy R&D.
> spend a significant amount of money to attract each new paying customer
Customers who pay subscriptions, not a one-time car cost. Every new car created requires upfront capital to build the car. SaaS CLV vs a car CLV requires WAY less costly touch-points after the initial sell.[1]
[0] - https://www.sec.gov/Archives/edgar/data/1562088/000162828021...
[1] - https://a16z.com/2014/05/13/understanding-saas-valuation-pri...