It definitely is, but the displays are relatively small get expensive easily. Price tags are cheap but not good enough.
Most displays need to be refreshed continuously, even if the content doesn't change. Only intelligent displays with an integrated framebuffer (or eInk type) can be updated at a low speed. But these types of displays tend to be small and expensive...
If you accept the "for starters" requirement as a permanent limitation, the main problem goes away. Doing that while showing a character count on an HD44780-style character LCD should be possible on most cheap MCUs.
The Pi Compute Modules are made for commercial use, with production guarantees and such. They are a decent substitute for the Zero. I don't know if second sources exist for any modern MCU, but maybe clones. Code control is under your control, it's all open source.
Doing such a project on a commercial level immediately changes a lot of the assumptions. Floating the idea of a few thousand devices to the right company will make them start talking to you and possibly even solve the display issue, and sourcing prices will decrease. Whether it's worth having to deal with local legislation on selling devices depends on whether you have access to an experienced company to start with...
As a hobby project, the high-resolution TFT display + driver board for a good price means ordering from China. The general sourcing situation doesn't get any worse by relying on a Raspberry thing.
