The term “lock in” to me sounds like a load of “sour grapes” by disgruntled competitors who realise that they are unable to compete with Apple.
The way I see it, the reason why Apple is doing better than ever (and why I believe this will continue to be the case) is because their long-term strategy of building a comprehensive ecosystem of devices and services is resonating with consumers. Apple products connect with consumers, and Apple is able to do so while pushing through iPhones that are priced higher than ever.
When a customer buys an iphone, they are not just getting an iphone. Instead, the iphone is a portal into an Apple world which offers benefits from entertainment solutions (TV+, Apple Music, arcade), the most powerful consumer computers in the world (M1 Macs) and incredibly personal computing (Apple Watch).
To put it another way, Apple is able to have such a comprehensive ecosystem because it is pretty much the only company willing to invest in building up said ecosystem in the first place.
This is the biggest challenge facing Apple competitors. It is no longer enough to simply come up with an iphone alternative. They need to come up with an even better experience than what the Apple ecosystem currently offers.
Can it be done? Looking at the state today, my answer is a resounding “No”.
And this is why I believe Apple will go on to be even more successful. Consider that half of apple users still use only one apple device - the iphone. This means that they are using a lot of non-Apple hardware, which in turn means that there is still an incredibly huge untapped market of iphone users for Apple to market their hardware and services to.