I never really use it, but I am a fan of their rattle cans for a base coat. I half watched watched a YouTube video by Andy's Hobby Shop, he said it has been very hard getting Tamiya in for several months now, going back to July or so.
Likely increased demand with most of the world locked down to varying extents and people needing something to pass the time, and perhaps supply side production problems if the Tamiya plants have staffing issues and/or their own local lockdowns.
Back when I went to stores with a hobby department, it seemed like everyone suddenly had a Tamiya rack now, keeping that supply chain demand probably isn't easy either.