I'm sure a lot of the salary cap gurus here know this already but I read this article on Reddit which explains why, due to Covid, it made financial sense for Gordon (and also Avery Bradley) to opt out of the last year of his contract:
https://www.reddit.com/r/nba/comments/jxfi01/when_34_million_is_not_34_million_a_case_for/John Karalis made the same point in an article back in October, about how his $34m option is really a fake number and why covid means he will not get that much.
https://www.masslive.com/celtics/2020/10/gordon-hayward-contract-why-his-34-million-option-is-a-fake-number-why-covid-could-make-him-opt-out.htmlThe thesis of it is this:
The league and the players split Basketball Related Income, or BRI. That includes television money, tickets, and anything else directly related to the game. The league puts out an estimate of what that is going to be before the season, sets a salary cap based on that number, and we all get to enjoy basketball.
Players divvy up their half of that pie. So while we hear specific numbers about how much a player makes, the amount of money that actually shows up in their bank accounts is actually a percentage of their portion of BRI, based on their contract.
“The salary cap is really just sort of a construct,” explained Ryan Bernadoni on the Locked On Celtics podcast (embedded below). Bernadoni is a salary cap expert and former Celtics blogger. “(If a) player is gonna make $5 million, they don’t actually get $5 million, necessarily. What they get is $5 million divided by all of the salaries paid in the season. It gives you a percentage, right? That’s .07% of total salaries times half of revenue. And that’s what you get.”
“They take 10% of every player’s check and they put it (aside)” Bernadoni explained. “That 10% is enough where under normal circumstances, you can adjust it up or down and give them the right amount of money for the year.”
These are not normal circumstances. Players normally get some or all of that money back, but in May, the league began withholding 25% of players' checks because of the league’s COVID-19 hiatus. The league’s revenues took a big hit, and that additional withholding is probably money the players probably won’t see.
By opting into $34.2 million, he’s ensuring that large number will give him a significant piece of whatever the players split of BRI is, but if the league keeps the entire 25-30% escrow payment, Hayward could lose out on more than $10 million of what he was expecting.
However, if he opts out and signs long-term, he can take the one year escrow hit on a lower number and hope things go back to normal. As his contract progresses, the escrow situation goes back to normal and he would end up keeping more of his money after this season.
“If you’re Gordon Hayward...I can think, well, I could bypass this year, I can opt out and re-sign for a longer term at lower dollars,” Bernadoni said. “The possible advantage is, if you’re gonna lose 30% of your salary in one year, it’s better to lose 30% of 20 million than 30% of 34 million.”
https://www.masslive.com/celtics/2020/10/gordon-hayward-contract-why-his-34-million-option-is-a-fake-number-why-covid-could-make-him-opt-out.html
Here's a table showing 2 hypotheticals for Gordon:
1) he opts in to his $34m, then signs 2 1 year deals of $20m and $15m for a total of $69m total; or
2) he opts out and signs a 3 year deal for $22.5m each for a total of $67.5m

The calculations are on the reddit link for anyone who wants to review them so I won't repost them here but it illustrates how he could end up taking home more actual cash - $58.5M for hypothetical 2 vs $55.4M for hypothetical 1, because of the big Covid hit this coming season. And it shows how he might end up taking home considerably less than the $34M that he was owed this season due to the overall reduction in league revenues due to Covid.
Based on this, there's financial sense for Gordon to opt out and find a longer term deal that pays him more money due to the way that Covid has hit player incomes this year and the coming year. Whether that is a longer term deal with the Cs or with another team who can sign him outright or get him via sign and trade is yet to be seen, I'm sure we will find out in coming days. So feel free to keep the hate for Gordon coming
