Share buybacks are part of the self-reinforcing loop that drives stocks higher. When the Fed pulls back, buybacks will get more expensive. The risky game of loading up the balance sheet with cheap debt to buy back shares, rather than invest in productive assets will balloon interest expenses.
If new assets were really productive (generate a higher return becuse ther are more jobs, tax revenues, etc.) but if they are improductively invested in price bullbes (stocks and flats) then the winners are the previous holders of assets , and the losers are the foreign buyers who end up overpaying as well as all Americans affected from the burst of the bubble.
The key is how foreign capital is invested productively and most of it isnt because its money looking for a relatively safe haven not money seeking for a genuine investment opportunity.