So Twitter was at $70 per share a year ago. So what? Jack Dorsey was CEO a year ago, too. The share price was $33 less than a month ago. But, despite an absolutely incredible roller-coaster news cycle, things have been definitely trending down at Twitter ($33/share last month), which was reflected in its share price. The current executive team (and Dorsey) had wasted time focusing on things that didn't matter instead…
To make a successful hostile bid, you need to pay not just "more than the current price", but "more than the holders of 50% of current shares believe the company to be worth". Usually bidders use analyst price targets to guess at the distribution of holders' internal price targets.
This is what makes it so difficult, and why this bid is very likely to be rejected.
(This is easier to explain with a white board, tbh.)