The one thing you know is that full blocks are bringing much profit for miners than not filled blocks. On the other hand, the Bitcoin developer team want to remain the block size and not bigger blocks while a part of bitcoin community wants bigger blocks. In the next fork, the altcoin B2X brings bigger blocks and the SegWit functionality remains.
Woldn't implementing lightning network require even bigger blocks at some point? Like 100 MB block size to cover all the needs of network for billions of people?
Yes - all those 2nd layer techs need to settle on-chain and will either need more block-size or higher fees. Making ordinary on-chain tx way to costly for small users ( yet told to run a relay node each).
The biggest issue with these new techs is, that they are brand new compared to on-chain transactions and so not really same secure or rather insecure by many orders of magnitude.
All ppl that promote those things will mostly not tell you about risks and disclaimers as it would be usual for any financial solutions.