The price of beef does not include the environmental impact so I'm not sure this is a good indicator of the impact of making a product. Beef/Milk in the USA is also subsidized...
Obviously at the margins there are costs to environmental impact that may or may not be realized in consumer pricing and there's lots to argue about on the regulatory side.
But in general, if you have to "equivalent" products shipped and produced in bulk, and one costs 4x as much as another (roughly where "beef vs. soy protein" lands for the consumer), it's a really good bet that the cheaper one involved less energy to produce.
And to speak to your point specifically: if it were simply a matter of reducing per-unit R&D costs by achieving economies of scale, they should be selling below cost so that they can grow unit volume. It's hard to achieve economies of scale when your product is more expensive than the competition.