Yes, because like I said: marketing. "Protein Shakes" are a bigger/more popular niche than "Meal Replacements", so naturally a lot of products are gonna double dip and try to claim belonging to both categories. But that's irrelevant because what matters is the actual nutritional​ composition of these products.

Soylent has 20g of protein per serving, and most of the products listed above are also in that 15-30g of protein range and share most of the same micronutrients, so functionally they're about equivalent. The only real differences between all these products are marketing, price, taste, "recommended" serving sizes, and small tweaks in nutrient ratios. Other than that, they're all pretty interchangeable.

The "Recommended Serving Size" for these products can effectively be considered as just another part of the marketing. Comparing them based on their superficial face value is as useless as comparing apples and oranges, you have to actually calculate the amount of nutrients per quantity of mass if you want to compare them thoroughly.

Right off the bat, it's worth noting that Soylent has an unusually large serving size of 106-142g [0], compared to the products listed above which have an average serving size of 30-40g, and therefore position themselves as being 'better deals' because they can claim to have more "servings". But otherwise the nutrient ratios are quite comparable and it's disingenuous to suggest otherwise.

[0] https://faq.soylent.com/hc/en-us/articles/204409635-Preparin...