Try looking at it this way:
The price of PTS at any point in time represents the market's assessment of the potential of the entire BitShares industry.
When a DAC spins off, some of that potential spins off with it and the price of PTS drops by the amount of future potential that is no longer predicted by PTS. Nobody minds though, because they now own shares in both and the sum of the two is greater because the value that moved has gone from potential to actual.
So when donated PTS shares "split" the donated value just moves into different buckets. It is still there to help fund the growth of the industry as the donors intended. To the extent that these spin-offs are successful, the seed money available to maintain and promote them grows too.
And thus each successful spinoff replenishes the supply of funds expended to create it, making those funds available again for the next DAC in the development queue. With luck, the funds will grow exponentially, making the number of DACs we can fund in parallel grow exponentially.
This is what we have promised to do with spinoffs from donated funds. We did not promise to leave them idle or to burn them. That would be poor stewardship indeed!