A few reasons for the drop coverage here. The video below describes a few of them well + shows that the team did switch up their coverages the last 5 minutes and got burned for them when 1). Horford switched and got blown by by Steph 2) the C's trapped and Green did his thing as a 4-on-3 distributor. That said, I think we will vary our coverages a bit more the next 3 games but still start out in drop.
1) Ime said in a press conference a few weeks ago "Unless you're Kevin Durant, I'll let you try to beat my team by yourself." It worked for Giannis and Jimmy, who both put up big numbers but had sub-par efficiency and ran out of gas as the series ran on. We also have shut down role players like Bam, Herro, Lopez, and Jrue quite effectively with this strategy. Frankly, I believe it's what has allowed us to win the 2 games we have. Curry simply ran out of gas in both Game 1 and Game 3, scoring much less in the second half.
2) It neutralizes Green. When we double or blitz Curry, the Warriors are the best team in the league at getting rid of the ball quickly to a roller (Curry as the passer) and the roller running essentially a fast break from the three point line in (Green as a distributor and driver in a 4-on-3 situation). This initial advantage early in the shot clock is what drives the infamous Golden State ball movement and gets an entire team hot. By not doing this, we get their non-Curry players out of rhythm. It's not a coincidence Green, Thompson, and Poole have largely not looked like themselves this series.
3) It's our best shot at protecting the rim and rebounding. The C's have run a weird drop-type scheme all year where they pre-switch and drop as much as possible both on and off ball to keep Rob near the paint. It's the observation that a lot of analysts made in February where Rob is an elite help defender in the dunker's spot. Curry is just that generational player that can punish even a small drop by shooting 5 feet behind the arc.
4) With Green in the game, consistently playing drop is a hugely effective strategy because the Warriors no longer use him as a screener and just put him in the corner. This plays into points (2) and (3). This has allowed guys like Rob and Marcus to "guard" him while simply playing free safety and mucking up the paint and covering for any missed rotations along the arc. Again, I've been very pleased at the shot quality the Celtics have allowed. Other than Curry going God mode, there have been very few shots this series that I've been mad about when they were released.
5) That said, Curry is an all time great, and the C's need to make him think a little more.
I think it's worth noting the C's have held the Warriors to below their season average in scoring (100, 107, 108, 100). Although the Dubs are scoring quite well pace-adjusted (120something per 100 possessions), the game seems to largely be at the tempo Boston wants (except when they turn the ball over or give up offensive rebounds. The Warriors had more than 30 fast break and outback points in Game 4). Boston has simply not looked good on offense. In Games 1, 2, and 4, they got enough stops throughout the game and in crunch time to win.
Here's the video. They do a breakdown after every game, and they are by far my favorite basketball content online today:
https://youtu.be/t6_vawdzRok