@TomE to summarize it comes down to profit margins. I could list a hundred reason from complete lack of vertical or even horizontal integration to the manufacturing process which isn't in production but is already 5 years behind what a company like Tesla is doing. All of them will never be changed and as technology advances they will fall further behind. To put it as analogy Lotus is on rocket and that rocket is traveling slower and is further behind so it will never catch up.
As you mention, most of Tesla's advantages are very focused in profit margins for mass manufacturing. These come from vertical integration reducing middle men, low number of models with many shared parts, being a step ahead in setting up factories and battery sourcing, "gigacasting", etc. Pricing competitive advantage matters less at the $80k+ price point and up that Lotus lives at, where prices and margins between companies can vary significantly due to less price sensitivity in customers (see Porsche). As an example, Lotus had a ton of technically inefficient processes: extrusion requires a lot of assembly vs. stamping; adhesive bonding requires a wait time vs. welding; in general, Lotus relied more on hand built assembly vs. automated lines with product sharing like Porsche's 911 and 718. Yet Lotus could still offer similar prices. Not sure how Tesla are horizontally integrating as you say because they aren't buying out competition.
Tesla is perceived more advanced in R&D vs other OEMs because they can deploy their technologies faster. This is because they had a head start and because other OEMs can't change their "ships" direction fast enough. With batteries (4680 and silicon) and software I think they're actually ahead, but on motors and other fronts they're just faster to mass production with an uncompromised product. I think the power outputs of Rimac, Lotus' Evija, and Lucid (Lucid overall in other areas as well) demonstrate that.
Lotus has very few assets and workforce, meaning they can pivot to EVs much faster and effectively than Volkswagen, Ford, and GM with educating their engineering, not having to reuse existing ICE parts/platforms, and not having to rework existing factories. Lotus has demonstrated with EVs to show they have experience to potentially catch up or keep up. They've committed to a full EV transition and investment earlier than most OEMs after they were acquired by Geely, and they learned through the Evija. The Evija developed their experience with high powered motors, batteries that use high voltages for large power draw and fast charging, and the electrical architecture to support all of those. They can lean on the resources of Polestar, Geely's Chinese brands, and Nio for R&D and larger scale production.
In the same way Tesla had an advantage building an EV platform from scratch, Lotus is building an EV platform but can also greater optimize vehicle performance with a "midengine" battery without needing to compromise for other vehicle and passenger configurations like the skateboard battery requires. Lotus is also working with suppliers to develop products (batteries/motors) that best match their use case while also developing the platform in parallel to best accommodate those products holistically. And Lotus do some things to make a better product at the production quantities they work at. As a good example, aluminum extrusion and bonding are not good for mass production, but they're optimal for structural rigidity and minimizing weight.
Lotus has been working quietly on their EV backend and investing millions for years. If they're observing the market and think they can make a good/competitive product, I believe in them.
