It's a reflection of talent and power coalescing into an increasingly smaller group of European teams and leagues. Also there's more options now to watch the big leagues thanks to globalization, high speed internet, and increased tv coverage given how lucrative these big leagues have become.
As a kid I never watched the EPL because I didn't have a way how but I did watch the Eredevisie and Brazilian (and many others like the Mexican, Spanish, Italian) leagues cause those were on tv. Nowadays I only bother with the EPL and La Liga. Serie A is a corpse. Ajax, PSV, and Feyenoord were elite teams in Europe. Now Ajax is a farm team for the huge clubs and the other two are non-entities in Europe.
I've got less free time as an adult and more entertainment options, I only want to watch the best of the best.