It takes quite a bit of research down the rabbit hole to get to a tentative conclusion like this. Kudos!

More, bigger, faster, is not always better when it comes to building a worldwide network like bitcoin.

While we cannot know for certain how things would have played out, but I like to think that if Satoshi had already built LN (or similar) into bitcoin from the first public release, then the block parameters would have probably been chosen to be both smaller and slower. There are a bunch of other things, such as some privacy improvements, Satoshi would have included in this hypothetical initial release too, but here we are just discussing these block parameters.

Slower generation rate would have ensured early on that pretty much all small payments (coffees, pizzas, etc) would have been off-chain. So yes, there would have been a highly mature second layer earlier on.

Smaller blocks would have been easier to broadcast via other methods. For example, ideally the blocks would be small enough and slow enough that they could propagate easily via low power, long distance, radio protocols (LoRa and similar).

And yes, these changes (while unlikely to achieve consensus anytime soon, if ever) would probably bolster demand for a highly mature second layer.

Thankfully it is not too late and LN is continuing to grow.