Foldable phones will halt the phone's size growth
Phones are getting bigger and bigger in order to accumulate larger screens and provide users with a better viewing experience. However, with 7.12-inch phones like the Huawei Honor 8X Max, we've reached a point where even with bezeless design, making a larger phone won't make any sense. The reason for it is that it will negatively impact portability and if someone wants a larger device, he or she can buy a tablet with cellular connectivity instead.
Some say that AR glasses will eventually replace the smartphone as we know it and we will no longer be restricted to a small screen. With AR, you can project a screen wherever you like and in any size of your choice.
If you look at Apple's iPhone devices, you can see that Apple, like many other mobile phone manufacturers, is continuously increasing the size of its phones from year to year. Take a look at the size comparison image below, you can click on it to open it in the comparison page.
This shows a very clear look at the industry regarding phone sizes over the years. We can see the small iPhone 3GS from 2009 that was 115.5mm tall and 62.1mm width. We move on (I am skipping some phones) to the iPhone 5S from 2013 which is now even bigger (123.8x58.6mm), than we go to the iPhone 6 (138.1x67mm) from 2014, a big jump in terms of size. Then we have the iPhone X and XS that hosts a 5.80-inch display compare to the 3GS that had a 3.5-inch one and at the end of the comparison, we see the iPhone XS Max which is significantly taller than the XS and X and comes with a neven bigger 6.5-inch display.
You probably might be asking yourself will Apple continue to push the size of its iPhones even further towards 7-inch. We already have the iPad 9.7-inch (2018) model and as you can see from this comparison image below, there is a gap where Apple can continue to push things up a bit.
Now, the thing is that the iPad bezels are very large and it also has a much wider display. Let's take a look at how the two screens are compared without the bezels. This will give us a better understanding of things.
Well, we can see that the iPhone XS Max screen is way wider and smaller than the iPad. There is a big difference between the two screens, thus those devices are aimed towards different uses. Apple can theoretically bump the screen size of its future iPhones even more, even touching the 7.5-inch screen size line (Considering that it also reduces its bezels to a bare minimum). Whether Apple will "dare" to do it, well, only time will tell.
Tablets have their place and continue to have their unique offering in years to come. Many people will prefer carrying a relatively compact smartphone than having the need to carry a large 7" phablet in a small bag, it's just a matter of convenience.
That being said, once you try out a large-screen smartphone, it's hard to go back to a smaller screen. It's not different than getting used to a large desktop display in your home compared to a tablet. The thing here is that unlike your home when you are outdoors, you usually carry just a single device, and you prefer that device will be comfortable to carry around.
If there was a place for larger 7.5" and up mobile phones, I think we would have seen many other companies releasing such products, but the thing is that we don't see those. If you want to go up, you go with a table, and in return, you get a much larger display that can give you a completely different viewing experience than what your phone can give you.
We still have a place in the market for tablets with edge-to-edge displays, bezeless designed. Just look at the iPad 9.7-inch bezels - they are huge!
I do think we reached a point where making larger phones will just impair the user experience and those phones if pass the 7-inch screen size mark will become too bulky and inconvenient to carry, regardless how thin they are.
This brings us to foldable displays. Foldable displays is a technology that can allow phone manufacturers to provide users with even larger tablet-size displays but maintaining a compact size device. The screen will be folded when not in use or when particularly in use with apps that just use a part of the screen. When you want to use it as a tablet, you fold it out and now you have a very big tablet-size screen to use with your apps.
That time will come, and some say that we are going to see phones with retractable folding screens already in 2019. The technology is already there, and it's a matter of time until it reaches the market. Apple will probably be there as well, but I do expect Samsung to be among the first to release a foldable display phone.
Foldable phones will probably mean the end of the tablet devices as we know it. I actually read a rumor that Samsung is going to release a foldable phone this year, in 2018. Anyways, the future is very interesting and I personally can't wait to see how those phones are going to look and function.