OP means something more like "a security which appreciates on average faster than inflation", AKA an asset I can purchase and hold and sell later for more than I paid for it+improvements in real terms.
I think we should shoot for house prices increasing at exactly the inflation level (after a correction for current high prices of course). To me, this would be good enough to be considered a 'good investment', and wouldn't be unfair to future generations.
I don't mean to be a jerk, and this isn't directed at the parent poster, but when someone makes an argument that contains an unsound point that in a vacuum cannot hold up, that unsound point critically degrades the entire argument.
When someone includes statements in an argument that can be trivially disputed, they should fully expect those weak points to be disputed. The rest of the argument, imo, does not deserve critique until the trivially disputable points are resolved.
I didn't make an unsound point, there was a misunderstanding by you. When talking about financial assets or investment, accessible means affordable, but affordable is a relative term, whereas somethings accessibility is a useful observation - "can working-class people buy one easily?"
I think the parent commenter meant "investment" in the narrow sense of "financial security" and not in the broader sense of any activity that generates a figurative return for the effort applied — in the case of roads, turning government action into economic activity.
Roads are a perfect example of a good investment that is accessible to all. It's called a "common good", and it exists.