The Internal Combustion Engine has taken its modern form by improving on many technological fronts to improve its performance, some of the commercially viable technologies include:
Variable valve lift timing engine
Turbocharging
Cam-less engine
Active alternator
Atkinson cycle engine
Direct injection engine
Cylinder deactivation
Also referring to the latest report "Assessment of technologies for improving light-duty vehicle fuel economy 2025-2035" which indicates the latest technologies to improve fuel economy (4 Internal Combustion Engine-Based Powertrain Technologies | Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035 | The National Academies Press (nap.edu) refer Fig-4.2) does not mention any technology that works to improve on the inefficiency of the Slider Crank Mechanism.
Mention that none have identified the demerits or have attempted to improve the Slider Crank Mechanism or find an alternate to improve its force conversion ability, this is where the start-up comes in, to point out the demerit and find the alternate solution for Slider Crank Mechanism.
Nissan and Honda have developed multi-link crank engines with the motive to attain Variable Compression Ratio and Variable Stroke Cycles respectively, which stands as proof that multi-link crank engines like the proposed Five Bar Crank Mechanism for higher efficiency or torque can also be commercially developed.