GPL software should use the same predatory tactics as proprietary, and trend chase. Focus primarily on trend-chasing and marketing, focus on getting cash by any means necessary other than not making the source available. Market hard, dual license.
Dropping a license check in (as long as it's not obfuscated or intentionally confusing) is very cool in my opinion, and I wish you luck. Thanks for adding to the commons.
I'd rewrite this as "People who want to make money from GPL software should ...", because GPL software in general doesn't have to have a commercial goal.
>trend chase
>getting cash by any means necessary
>Market hard
I think you have a distorted view of the commercial software world. Of course you can find some bad apples but the majority just isn't like that.
Yes, it's AGPL with source code publicly available, but if you remove that license key check yourself, you have to make it public, effectively broadcasting that you don't pay for software. In a way, it's naming and shaming. The alternative is using the fork of someone else who has done so and complied with the license, but then you're suddenly dependent on some random downstream and who knows what else they have mixed or might mix into it or just give up merging from upstream eventually.
...for the users of the modified software, not everyone. If the only user is you, having the source code on your own machine is enough.
I think this approach of dual licensing is well suited when the intent is to let people audit source code freely for evaluation or personal use purposes, but then pay up when they wish to use it in their public/commercial projects.