While this is generally true, land values do tend to rise over time simply because the population increases and thus there are more people competing for a finite resource. It's a value change that can only be measured accurately over decades, however.
Indeed; although there is a historic counter argument to my point. Not so long ago land was such an important economic asset and it was concentrated in so few hands that those who owned any could easily live off their ownership for generations and even accumulate more wealth in the process, while everyone else was doing the actual labor. It was called the feudalism. And that is precisely what a deflationary currency would result in.
That is a nonsense comment. First off, feudal lordships were functionally mini-governments, and thus the quality of life varied significantly; and the only practical difference today is that your lord is an elected political class and your lands are much larger. The government still takes a portion of your earnings regardless of whether or not they let you think that you own the means of production or not. The perception of practical differences are a matter of technicalogical progress and educational propaganda.
Second, the currency unit has little to do with this. The rise of nation states (as opposed to fuedal lordships) occurred during a time period that there was literally no alternative to gold, silver, copper and barter.