it's a nightmare that will happen if it is not fixed. in the future there will be many companies or payment applications that will accept bitcoin, but if this problem is not resolved then bitcoin will be blocked, and after that bitcoin will experience a very deep price drop.
block is an offensive word but no it wont happen they dont need to block btc if they dont want to partner or use it but they can easily say no . delays in transfers are bothering but people keeps on going . the btc team are still working on to fix the issue because all are going to be happy once the main issue are solved .
if in the future there is a crypto currency that has more functions than bitcoin and very fast transactions, bitcoin will be replaced by that coin.
litecoin is the second bitcoin and it has the quality that you are looking for but litecoin still remains an altcoin . same to other altcoins that can also function as close to litecoin but for the record btc still holds its title .
1st point
There's no BTC team working out on the delays of transactions. There's a possibility for this technology to be banned, and there are already countries wherein it is. And the reasons are not because of issues regarding transactions but because of lack of taxation, and some reasons are "involvement" with illegal activities or maybe because they are threatened;they have their own reason. IMO this technology will receive full acceptance once regulation occurred.
2nd point
Ethereum I think is next to Bitcoin and not lite coin. Cryptos which will be more accepted in the aspect of scope of usage are probably fiat based because it will be more supported by the governments.