> Right now there's this trend where companies take the benefits of open source for themselves, then toss aside the open source community when it looks like it might make them a buck
The narrative you're trying to paint is misleading at best:
> It’s important to remember that Sentry “the project” has been developed almost exclusively by employees of Sentry “the company”; millions of dollars have paid the salaries of engineers, designers, and product people to produce the software we know and love today.
They are the primary contributors to their own product and the existing "community" that use in-house versions remains unaffected, they can continue to use modified versions and contribute back features everyone else can benefit from, which I see no reason why they wont continue to do as they can continue enjoying all the benefits of being able to freely use their own hosted versions. But those outside contributions are going to still pale in comparison to the vast majority of contributions that Sentry makes in improving their own product, the most valued contributions Customers are going to make are in the form of feedback, feature requests and detailing how they're using the product.
They're definitely not "toss aside the open source community", their BSL is specifically targeted so that "it won’t change anyone’s ability to run Sentry at their company". You're insinuating the opposite that they're discarding their existing community, when their license is specifically targeted to allow continued free usage by their customers and is only designed to prohibit their competitors from taking of Sentry's investments and using it to compete against them.
This change gives them a more sustainable business model that better protects their investments against competitors reselling their efforts and undermining their business model that's directly used to fund the investments in making a better Sentry product. It's a win for Sentry the product and company and their customers, the only losers from this change are cloud monopolies and Sentry's competitors who are more than welcome to use their own efforts and investments in creating their own competing product.