>The logical thinking is: are they going to make me dependent on some cloud service to develop for Arduino?
The logic to me is "how can they do that?". You don't need a cloud service to program a microcontroller and they can't force that upon you even if they'd want to since the arduino board is not an iPhone.
They could very much force it on you, for new units at least - depending on what micro is on the boards, they could potentially very easy start shipping them with locked bootloaders (and disabled JTAG/SWD porrts) that would only run binaries that are signed by them.
They could potentially have their software load a unexpectedly re-flash existing units with a locked bootloader too, it would just be harder to keep the key secret (because the tool flashing the new bootloader on the first time would need to know it)
Yep, it's fine to not consider future versions when you do say hobby projects, but I worked on a commercial Arduino based project that's supposed to run on top of poles on solar. For that I very much care if they plan to make it cloud dependent... and I don't assume sanity on part of management.
Don't know what Adafruit has a problem with, but the above is my problem.