BMW is now running prototypes for the X8, which will be out next year. Mercedes is rumored to be working on a GLS coupe to rival it. Lexus has issued a number of new trademarks - RX 350h, RX 500h, TX 500h, TX 350, NX 450h+, RZ 450e, etc. Dec 5 (3 days ago) was 3 years since we saw the LF-1 Limitless concept, and in that time, we've had almost nothing to go on with spy shots or rumors. The world has continued to move forward and it seems to me that the LF-1 has been left behind, and perhaps that makes sense. Looking at Lexus' future with new AWD systems, Direct4, bigger batteries for hybrids, eTNGA and more, I think it's possible that the LF-1 has been squeezed out of the portfolio.
My personal opinion is that an all-new 2 row, upgraded RX, all-new 3 row TX CUV, new GX, new LX and then RZ as speculated to be a midsize CUV coupe have probably not left a space in the lineup for the LF-1. If anything, I think the RZ will take a lot of cues from the LF-1 and come to market as a premium product, but under the midsize "R" name instead of "L" for flagship as we have expected.
With no trademark filings and no prototypes, I think it is hard to see how anything will come of the LF-1 as it was originally shown and as we expected. COVID is not really much of an excuse - every other automaker, Toyota included, has been pumping out new models at an incredible rate.