I'll be honest, I really don't get what you're arguing now. You seemed to be implying that Starbucks were responsible for increasing spending, but now suggest that it's impossible to prove.
Spending has increased in the past 40 years because disposable income has gone up. Spending has decreased in the past 10 years (in real terms) for the same (opposite) reason. When people switched from Tesco to Aldi, that wasn't Aldi 'increasing spending', nor was it Tesco doing anything wrong, it was people reacting to changes in their economic circumstance by spending less. And yes, now Aldi undoubtedly contribute more taxes to the economy, but Tesco contribute less.
And of course coffee sales have exploded in the past 30 years. What has happened to tea sales in the same time? Which is exactly my point. People will spend what they can on something, and companies just fight for their slice of a pie that already exists. They don't bake the pie. They don't magic more disposable income into people's pockets. If people spend money on coffee, by definition, they won't spend it on something else, and that area of the economy will suffer as a result (and hire less people, and pay less income tax).