“All Total 132 133 138 152 146 139 127”
Collapse? What Collapse? That looks more like noise around a more or less constant number. You are reading way too much into differences from one year to the next. To spot a true trend you should consider a rolling mean rather individual points.
Any given Harvard undergraduate’s experience of the campus will be spread over four years of enrollment. In the above total Asian enrollment numbers the 4-year rolling means look like this:
139, 142, 143, 141
Having smoothed out the year to year bounce you can easily see there is no significant trend and certainly no collapse. The degree of “diversity” provided by foreign Asians that a student who enrolled in 09 experienced vs. that experienced by a student enrolled today is almost exactly the same.