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).
This is not true.
Lightning does not need to be settled on-chain. This is wrong. Once money is on the Lightning network, it can stay there until a user wants to use it on-chain instead. Settling on-chain is not necessary at all, and so because mining is not involved in Lightning transactions, fees can be cheap or free (the only cost is running your computer and it's Bitcoin node, basically nothing).
For instance, if your friend sends some money directly to you with Lightning, you can charge a fee if you like. Just don't expect them to still be your friend if you do
(or to receive the money soon
)
This will not require 100 MB blocks or anything like that, as there can be huge amounts of money on Lightning all the time. Lightning transactions don't use block space, they are off-chain.
