Earlier quoted context omitted.
From the company perspective, performing buyback when market is high is just throwing cash by the windows to over-priced shares. If they wanted to distribute cash, they could just use dividends
Three things: 1. From the perspective of shareholders, and for the moment ignoring taxes, buybacks and dividends are exactly economically equivalent. If a dividend happens, you get some cash. If a buyback happens, the value of your shares goes up. Crucially, the amount by which each share's price goes up is equal to what the per-share dividend would have been . It's a useful exercise to work this out and convince you…
Wouldn't the inverse of this be true in buybacks though? If it's economically equivalent then buyback should increase the price and similarly increase the proportion of X in your portfolio - which would force you to rebalance (might have tax implications).
Generally agree with the main point.