In recent years, artificial retro environments have become fashionable in some care homes and developments. I can see that it's a positive approach to try to accommodate and support the perceptions of the resident; and artefacts from the time of a person's youth may create a familiar ambience and trigger memory for some people some of the time.
But I'd beware of investing too much (effort, faith, and finance) in such things, as they can become management gimmicks, not truly responsive person-centred care - which primarily requires human interaction. A "one-size" time-zone (e.g. 1950s street) is unlikely to chime with the mindset of all the residents all of the time - there may be a range of ages within a residential group, and even for the individual, different eras may be important (or conversely meaningless or disturbing) at differing stages of their condition. And how often can a home afford to update decorative features in response to changing social needs, when most now struggle to meet daily running costs?
Given how hard it is to second-guess a person's internal reality in the moment, it's really not possible to create a consistent (and future-proofed) "alternative reality" that will answer all the confusions and insecurities attendant on dementia; and a fake environment, however well meant, is fundamentally dishonest.
* This point added in March 2017.