But I don't think it is that fast. Bitcoin had been in the industry for more than a decade and yet only 4.2% of the global population is familiar to it.
Degree of fastness falls into the category of distinct where each person has different point of Views and in my point of view, this adoption rate is fast enough in compared to a one and a half decade. (15 years). But still, it could grow more if backed by governments and not manipulated by whales, money makers (greedy ones), illegal users (who use it for illegal activities). Then i think the adoption will be more.
But this adoption rate is going to increase soon, according to
cointelegraph, the adoption will increase by 10% till 2030. which means in the last 15 years the adoption rate was 4.2% and in just 7 years if it goes up to 10% then it will increase by 2.5 to 3 times.
And i have a question for dear op here that what's the source of your statement. Please share that too. Because i was unable to find one.