They just need to be "cracked" which basically means decoded via software like
WinOLS or
ECM Titanium which allows tuners to translate values and interpret maps. It's like having the Rosetta Stone. Once they know how it was originally written, they can modify and rewrite as needed. Then those custom maps (which do things like raise rev limits/boost and tweak fuel maps/ignition timing, etc.) can be used on a vehicle via a reflash (retunes the factory ECU), piggyback system (works in conjunction with the factory ECU), or a complete standalone system standalone system (Hondata, AEM Infinity, JWT) which completely replaces the factory ECU with their own hardware and software.
More info on the different methods of tuning this video:
Lotus also doesn't sell a ton of vehicles so there isn't a lot of aftermarket support. Tuners generally aren't going to spend the R&D time to develop and market custom tunes (or any parts) if it's not going to be profitable for them due to a smaller customer base. Also the supercharged 2GR platform is already tuned by Lotus, so there isn't
too much more potential without other major upgrades.
For comparison sake: