That of course can cause some problems with modern technology. Leadwerks just like Unity and most of the big commercial engines use deferred rendering now. This is fast, when you use different lights and many shaders at once, faster than old forward rendering. But it also requires shader model 3 (available since how long, since 2004?). So on modern and moderate aged hardware it is just the better solution.

But when you have stone-age hardware, then Unity scales better for sure. It can downscale from deferred lighting, to forward lighting, pixel lighting to vertex lighting and even harmonic spherical lighting. Thus it can not only render on very very old hardware, it can also run on different platforms, mobile devices and consoles. This scalability is even part of their rendering optimization. When you have 8 lights visible at the same time as an example and you dont configure them all to be "very important", then Unity renders only the nearest of them as pixel lights, a few will be vertex lights and another few harmonic spherical. So it still renders faster than most engines forcing all 8 lights to pixel lighting.

But this also shows that you dont have the same quality on each platform. It might render faster on your 6-years old PC. But it also scales down to a lower quality.