I don't see what's wrong with this post that it should be downvoted like it has been. I personally agree with this sentiment. It's like the developers who immediately rush to massive scale when all they've been asked to build is effectively a prototype. I've seen it time and again... they get bogged down in making sure the app can scale when they have yet to have a single paying customer for the product. At that point, they don't even know if there is even a market for the product and they're trying to build something that millions of users can use right out of the box. The priorities are off.

If a combination of back-end processing with some vanilla javascript, or jquery will get you to market for your first 100-1000 users (which, we know it will because that used to be the only way we could do things, on much less powerful hardware no less) then I say go with that. In the mean time you can work with the stakeholders to put together a strategy for scaling up as demand increases.