Sedans are going the way of the station wagon. I lament the loss, but there's nothing that can be done about it. The market responds to what is favored.
IMO, the TLX had some pluses and minuses. I looked at a TLX Type S before I got my ES350. The TLX was much "sportier", but honestly the back seat was smaller, the fuel mileage was not nearly as good, and the weight was much higher. And I couldn't find myself wanting to deal with the wonky way the PRNDL buttons work.
Most SUVs now are indeed car-like in the driving dynamics. This is a big parts of the dearth of sedans. I can tell you my test drive of the CX-90 blew me away. I can't believe a vehicle of that size and proportion can drive like it did. Alas, the CX-90 fails the "purse test" and "stroller test" and simply isn't anything at all close to what a family vehicle should be. It's beautiful, and the engineer in me was duly impressed by the amazing driveline and chassis dynamics. But overall the vehicle just misses the mark in the little ways that matter most. The Sienna and Odyssey have nothing to fear from SUVs of this kind.
If the typical SUV drove like my GX, then sedans would never disappear. The GX is absolutely old school truck, body-on frame with a live axle.
But it's pretty hard to sell people on the lower roofline these days. The advantage of better aero at highway speeds and lower CG is just never a real world factor for many buyers. Not when modern tech allows those huge SUVs to still deliver better mileage and to handle remarkably well.
On my recent trip, I saw a newer Escalade zipping through traffic at well over 90mph. Putting aside the absurd driver, I couldn't believe that thing could transition lanes like it did. This was a TALL and heavy SUV and it was showing little to no body roll and quite impressive transient response. I think they have 22" wheels now.
There are some ways in which the shorter roof vehicle will always be superior. But those ways just aren't relevant for many buyers now, who'd rather have the headroom. At to that the OEMs who need more room for complex hybrid and EV drivelines, and the incentive they have for larger vehicles.
It won't be long until you simply can't find a new vehicle for sale under 3500#. The average is already WELL over that, I'd think.