I guess they can be influenced by new laws being passed by politician, then industries some disappear some new ones appear. For example, the US textile industry is almost gone, and textiles are used in interior design ...
Social conditions that may affect design are:
• social status symbols
• lifestyle
• employment types and practices
• demographics
• identification with and / or belonging to groups, social
No it would not be because if you are traveling to other places outside of disney property, you would most likely spend money on food their as well. The dining plan is good when the entirety of your trip is on disney property because you know you will use all your credits