The report is too long but I'll say the following.
Today, Pakistan's and India's GDP per capita is about the same. So currently, sporting facility, especially in cricket, are more or less the same. Yet Pakistan is a worse team. It's not because of economic development that India has a better team. It's because at the present, it has better players.
Go back to 80s and 90s. Pakistan's GDP per capita was about 300-500 over that era. Yet we had a very good team.
Look at England through the 80s and 90s, and most of 2000s. Developed country, yet a pretty crap team.
Same goes for Sri Lanka. Not high GDP per capita, yet they have a very good team for about a decade and a half now.
Sports goes in cycles. I think there might be little correlation with economic development, as you say because it might mean more facilities, but it's not a huge correlation IMO. If you think statistics, you'd know that positive correlations range between 1.0 to 0.01. A correlation between 0.67 to 1.0 is very high. My personal guess is that the correlation is between 0.1 to 0.4. Not that great.
More importantly, however, I think you need to look at what's being said. What's being said is that economic development causes a team to become good. Not just correlation is being implied there, but causation. That's something that's obviously not true.