Using FreeBSD jails you can easily host hundreds if not thousands of web applications and services on a single server having the specs mentioned by the OP. This practice isn't even noteworthy in FreeBSD land as it is so common.
I've always found Wolfram Alpha surprisingly unhelpful and impossible to integrate into an enterprise application in a meaningful way in practice. This is an interesting paradox, I sometime call it the Wolfram paradox, here is what I mean:
Their platform is so sophisticated that it produces output in a non-deterministic format depending on your search terms. Therefore, if you want to consume their service by leveraging the full smartness and cleverness of their platform, your consuming application needs to be equally smart and clever if you want to do anything more useful than displaying their raw output in an iframe. This means that you'd have to re-implement non-trivial parts of their platform.
The only way to solve this problem would be to restrict your input to a fix format to make their output more predictable. But at that point you'd in practice rather use a more specialized (and much less expensive) solution. The only use case I can see for this is either very complex computations for which either no other vendor exists, or requiring so much resources to run that their platform is the most convenient option. Or alternatively the interactive use case to iterate on a solution as part of R&D, which I believe is the main way people use their products.
This is not a shocking limitation per se, but their marketing messaging has long been suggesting that they have a vision where developers will heavily use the power of their platform to build a wide range of real world applications both in the consumer and enterprise space. My point is that this will never happen because of the aforementioned paradox. They have built an incredibly smart solution, but it sorts of have a curse by design preventing it from moving out of the interactive niche.
So I feel like you're right in that we can do a better job of explaining how to do this (I obviously work at Wolfram Research).
But I think it's very possible and a strength of ours. Wolfram|Alpha is used by many services, including now MS Excel which I think is a counter example to the paradox you mentioned.
