Scaling is really compulsory and not optional if we are to talk about massive global adoption. In fact, some are asking if the world is ready for bitcoin, but the more profound question is quite the opposite, is bitcoin ready for the world? And as of now, there is this constraint of scalability and it is not negligible.
Bitcoin had to to scale should it want more market activities and bitcoin knows exactly that. That is why we have witnessed a number of forks that took place in the past. This forks either soft or hard are proof that bitcoin will not stand still in the issue of scalability and that is good news for all of us.
That's true. But what really matters is that if Bitcoin scales, it should do it in the most decentralized way possible. It's been seen that on-chain scaling is not the most decentralized solution, but it has allowed other cryptocurrencies to perform well with low fees and fast transactions speeds. One good example of this is Bitcoin Cash, which has already scaled to 32mb block size for on-chain scaling without the Lightning Network. But, the downside of this is that it will make the coin more centralized over time since storage costs and bandwidth requirements would be a lot higher for node operators.
For Bitcoin, the Lightning Network seems to be the most decentralized approach to scaling, yet it has some level of centralization. Off-chain scaling would allow the cryptocurrency to perform as usual without the risk of compromising the whole network in case the Lightning Network were to fail over time. Sure, it relies on third parties to route payments and open channels, but it's the best solution available yet for Bitcoin to scale for the whole world to enjoy.
All in all, even if Bitcoin will never scale, that shouldn't be a problem since people would have the choice to transact in altcoins, while using Bitcoin as a store of value.