I read a biography of a British politician who was later elevated to the aristocracy (although I guess his family was somewhere between commoner and aristocrat prior to that). It said his family took a financial hit because of a decline in crops in the late 1800s. I dug it up and found out that the US was partly responsible for that actually because of cheaper imported grains. https://en.wikipedia.org/wiki/Great_depression_of_British_ag...
Many aristocrats relied on agricultural income from their property holdings.
Another interesting point is that it seems like the majority of titles were awarded relatively recently as in within the last 120-150 years. That doesn't mean there aren't some older ones but it changes the perception of them from being a centuries old group of warlords or relatives of the king to a group of lawyers, military officers, and politicians.
Yes-ish? I might have linked https://en.wikipedia.org/wiki/Corn_Laws#Repeal In many ways that repeal was a direct consequence of the Industrial Revolution, and the IR's "new rich" were often eager to acquire the architectural trappings of the old rich, pay staggering sums to marry into them, and other tricks.