Are you US-based or non-US based? US diesel emissions standards are among the most strict in the world. Other Japanese automakers like Mazda and Subaru have had successful diesel engines in Europe/Asia that don't make it here due to the difficulty in permitting them. Nissan went through the effort with the 32V Cummins V8 and it barely sold. I've driven the Jeep eco-diesel and while it was torquey AF and fuel efficient, it's a very expensive option (around $8-10K IIRC). GM has some decent lighter-duty Duramax diesels but they don't sell particularly well either. I think Ford canned their smaller F150 PowerStoke due to low sales too.
I live in diesel bro-dozer country and lots of folks around here have PowerStrokes. Cummins, Duramax diesels. The pre-2007.5 diesels sell for over the 2007 MSRP now (like $40K for a nice LBZ Duramax) due to their better reliability associated with earlier EPA standards that are less stringent. 2007.5+ diesels in the USA are a royal pain due to the add-on requirements and EPA mandates for software that kills your power and makes you stop if there is a slightest problem with the emissions systems. I've personally been stuck on the side of the road (rental Fuso box truck) due to a loose connection on an emissions sensor. This would have simply thrown a code in a gas vehicle that could have been fixed any time, but instead is started giving reduced power every few miles until you stopped. On top of the emissions stuff you have to deal with fuel/water separators, fuel gelling in gold climates, glowplugs, etc. No thanks.
Overall, Toyota brining a diesel here would be a big lift for what has proven to be a low-sales and expensive option - none of the light-duty diesel options from Ford, GM, Jeep/Chrysler, or Nissan have really flown off the lots. It's another example of an automaker producing something enthusiasts clammor for ( light duty diesel) and no one buying them.
A better approach would be for EPA to have light duty diesel emissions standards that are consistent with the rest of the world....but they don't. Air quality is prioritized over carbon emissions.