I know it's a non-answer, but it depends very much on what your use case is. Any global system where every node stores every transaction for all eternity will b

I know it's a non-answer, but it depends very much on what your use case is. Any global system where every node stores every transaction for all eternity will be limited in capacity. If that is a problem depends on what your use case is. Most cryptocurrencies work like that, especially since they were all more or less inspired by Bitcoin. The capacity to which Ethereum and Bitcoin can scale can differ by a constant factor at most. (Where the latter is likely at an advantage, due to smaller transaction sizes and simpler scripts.) Scaling Bitcoin to a global payment network for everyone's daily transactions is probably not realistic. But it could very well act as the clearing backend for such a system. (See, for example, Lightning Network.)