West Indian biggest issue is they are grouped of seven independent countries and all countries are having their own quota which is concern and sadly no one country able to have separate cricket board and his own team, so this is main dead point for them, and they are losing some very good and talented players and now sinking down day by day from all three formats surely in near future they will be able to have just good matches against teams like Bangladesh, Zimbabwe and Ireland because Afghanistan is also going to be very good team in next few years, and they will be not able to compete with them.
But with same structure West Indies have produced legendary cricketers and have ruled the cricket world for decades. Don't forget even with current circumstances they were able to win T20 WC in 2016. Every team has it own winter and summer, right now WI are in there winter stage but it wont last forever.
And Issues in Zimbabwe and South Africa are completely different from here because here mostly white guys are better in quality and blacks still struggling to adopt this all with some good love for soccer and rugby.
In SA the main issue was racism and political, whites were given priority over blacks nothing else. Now with change in govt, SA boards have adopted policy of giving priority to blacks.