Two things worth keeping in mind:
1) In the declining North American mid-size sedan market, it seems that each major Japanese carmaker is staking out a unique niche for itself, with only a bare handful of rivals. Toyota's Camry is almost the sole remaining midsize to offer a V6 option (alongside Ford Fusion Sport). Honda Accord has the broadest variety of clutch-pedal manual transmission offerings (on both 1.5-liter and 2-liter Sport models). And AWD options for the new-for-2019 Nissan Altima are rivaled only by Ford and Subaru. Could the latter move, if successful, spur Toyota to offer an AWD option on Camry?
2) The 5th-generation Toyota RAV4 debuting in a few months marks both a move to the latest Camry/Avalon/ES TNGA-K platform and
Dynamic Torque Vectoring AWD. And, for the 2020 model year, its larger Toyota Highlander sibling follows in its footsteps. Could these renovated models (plus the AWD-optional Sienna minivan due for its own transition to TNGA-K around the same time) create enough critical mass to make an AWD option for some if not all the TNGA-K sedans a more viable and profitable proposition?
1) Possibly. It could make Toyota think twice and offer an AWD format for the Camry/Avalon. If Camry/Avalon get AWD, ES will follow suit. But I would still tread lightly on this point. It really depends on how well the Altima sells overall and how much of those units are AWD. If the Altima, even with an AWD model, doesn't even break close to Camry numbers. Toyota will still edge it out and refuse to offer an AWD option. Because they are still net profiting high sales w/o the AWD.
The only way I see Camry/Avalon/ES having AWD is if the demand is there. Sadly - there is no demand for this. The Camry/Avalon/ES base doesn't crave this.
Due to the TNGA-K, Toyota can bring AWD at anytime. The biggest question is if they will. My money is no.
2) Interesting point. You still have to see if its profitable to make AWD versions of each specific car. I don't believe Toyota will add something to a car because they have the ability to do so. Toyota will do it when they feel like its time or their research says so. You can see this pattern throughout their line-up. They have done some things that seem slow and questionable in car enthusiasts eyes but it draws big dollar.
If Toyota's research concludes that Camry/Avalon/ES would benefit from an AWD, they will add it.
Wishful thinking as conservative as Lexus/Toyota is I'm hoping for a IS400 or IS450 model with a 3.5 v6 twin turbo for the next generation, and for the return of the IS-F with a 4.0 v8 that is rumoured to be in the LC-F. And I think Lexus needs to offer more individual options like the Germans, I really don't like that there is only 3 packages available for the F Sport and non F Sport. If I'm spending over $50k on a vehicle I want more individual options to suit my needs. Isn't that where auto manufacturers make the most profits, in options?
Based off my experience as a long time Toyota investor - I agree - that is definitely wishful thinking.
Toyota's business model is very conservative and unique. They want to milk the hell out of something before even considering replacing it or "improving it". The engines in the 2G Lexus IS was used for 10 years plus before Toyota was like "Okay. Lets change it."
Personally - I wish there is a Lexus IS400 or 450 too. That would make it a C43 AMG, 340i, S4, and Q50 RS competitor. But do I think it will happen? Probably not. Toyota cares about the profit margin. They know majority of Lexus IS sales are base engine models. The question is - would it be worth it for them to develop a TTV6 for the Lexus IS for low returns. Would it please enthusiasts? Yes. Would it please share holders? Probably not.
Second thing to keep in mind - we are in a SUV crazed market. With the UX coming out and the rumored high end crossover being in the pipeline, Lexus is probably more focused on SUVs rather than high-performance Sedans.
Last thing to keep in mind is that Lexus recently said they don't want to keep their line-up bloated like their German rivals. This means - they are more likely to cut models than add models. And when Lexus add models - it'll likely be profitable models (SUVs and Hybrids perhaps). Lexus getting on the EV train is likely as well.
Regarding your last comment - yes/no. It depends how you look at it. Yes - the vehicles tend to be more expensive when you have to add individual options in order to build it - like Mercedes Benz.
However - when you do fix packages - that's where the real money comes in. Because when you let people do options - they can option it just the 2-3 things they like. When the packages are fixed, they can offer a much of stuff in one package (some you might not want) for a higher price. Take a look how the Lexus ES is tiered.