Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
I assume you mean you have a Roku Stick. There is no "Roku flash drive". And Roku themselves are not a streaming service, with the exception of The Roku Channel. For all other offerings, Roku is simply the platform.
You have to ask those particular providers. Roku cannot alter where a channel is available. Only the provider has control of that.
And the likely answer is what you've mentioned. When they stream online, they are licensed to stream only in particular geographical locations. Remember that most streaming providers don't actually own the media they are streaming. They simply license the right to offer it, and that license costs money. The larger the area they offer the stream, the more the license will cost.
Are there ways to get around the geo-restrictions? Yes, but discussion of that is not permitted on this forum.
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.