If the bitcoin doesn't scale anymore maybe the bitcoin does not become famous and maybe we haven't forum now. Securing your btc is the good choice to have for now and if btc will not scale and worst fails, there could be changes of peoples choices on currency and bitcoin will not be recognized in different countries; yet it's current system is still developing and doing great as we seen the price of todays updates.
Yes. If Bitcoin never manages to scale, then people would simply choose to make their transactions on other altcoins instead. They've already implemented scalability features, making them capable of handling massive transactions per second without reductions in speed or a rise in fees. The only reason Bitcoin is still the top cryptocurrency in market cap, is simply because it has first mover advantage. However, one thing for sure, is that its market dominance has been greatly reduced, because people have migrated to other altcoins.
On the other hand, if scalability solutions such as the Lightning Network becomes successful, then Bitcoin would mostly likely replace altcoins over the long term, as people would switch back to Bitcoin for their daily transactions. The benefits such as minuscule fees, and instant speeds are too hard to ignore for Bitcoin once LN is stable and active on mainnet. As such, many altcoins existence would be questioned (like Bitcoin Cash), since LN would be far superior than simply increasing the block size.
Despite this, no one knows what will happen in the future, thus it's best to wait and see what happens with Bitcoin over the long term as a mainstream cryptocurrency for payments. Just my opinion
