Hardware demand and acceptability is based on two factors, space and time. Today space is no longer an issue, there are already single hard drives that have 6TB or even 10TB in capacity. The issue in modern world has turned more towards time and computing power. Most modern day CPU's can handle the future, however each CPU has its own life cycle. The core i3 is the lowest of the low, in modern CPU lines. Before the introduction of 7th and 8th gen Intel Core processors, Intel Pentium and Atom were the lowest of the low. Now none of those two processors are ever found in any new PC or laptop. Core i3 it self is already known to have many issues with its implementation for the very demanding Windows 10 OS. Many devices with Core i3 do not last long on average, usually only a year and a half max before newer software takes a toll on the CPU's much lower processing power. This is not the case for the i5 and i7 with their superior processing power. In the modern world, there is very little use for the Core i3, a majority of the public use Core i5 or i7.
Many laptop manufacturers rarely if ever for, non-workstation or non-professional laptops, mix a i3 and discrete NVIDIA or AMD GPU together on the same device, as it diminishes the purpose of there being a Core i3 in the first place. Core i3 purpose is mostly for lower power consumption and non-demanding workload, which is opposite for what NVIDIA and AMD discrete graphics are meant for. The problem is that many everyday applications are now moving towards recommending their software to be used on discrete GPU's rather than integrated GPU's. One such example of this is Firefox where they intend to place NVIDIA as a default renderer on devices that support it. <---Link is to the Firefox Beta release notes for version 67beta.
The use of only integrated graphics actually posses, a greater security risk to the user, compared to software that runs on discrete GPU. The reason being is that a majority, if not all, System UI or Graphical instances run mostly on Integrated GPU only. Any holes in the security of the Integrated GPU software, and a nefarious software or plugins in the software running on the integrated GPU could wrack havoc on the system process running on the Integrated GPU. Basically a discrete GPU is used recently by software developers as a security layer to prevent harm to the users system from any software plugins or software, that try to leverage any security vulnerabilities in a integrated GPU.
Another issue with the Core i3 is the high variety of CPU branding, as well as the competition with AMD. With the release of Intel Core i9, now there are 4 lines of modern Intel CPU's. It's a well known fact that manufacturers do not use all CPU's that Intel is currently manufacturing. Then there is the AMD CPU's that are crowding the space. Basically with this crowded space, there is little room for Core i3 to thrive.
Core i3 is currently a x86 or x64 architecture, thus unsuitable for use in low-end electronics like smartphones, that require ARM based CPU architecture. It would require Intel in investing to make ARM based Core i3 CPU's.
Many laptop manufacturers rarely if ever for, non-workstation or non-professional laptops, mix a i3 and discrete NVIDIA or AMD GPU together on the same device, as it diminishes the purpose of there being a Core i3 in the first place. Core i3 purpose is mostly for lower power consumption and non-demanding workload, which is opposite for what NVIDIA and AMD discrete graphics are meant for. The problem is that many everyday applications are now moving towards recommending their software to be used on discrete GPU's rather than integrated GPU's. One such example of this is Firefox where they intend to place NVIDIA as a default renderer on devices that support it. <---Link is to the Firefox Beta release notes for version 67beta.
The use of only integrated graphics actually posses, a greater security risk to the user, compared to software that runs on discrete GPU. The reason being is that a majority, if not all, System UI or Graphical instances run mostly on Integrated GPU only. Any holes in the security of the Integrated GPU software, and a nefarious software or plugins in the software running on the integrated GPU could wrack havoc on the system process running on the Integrated GPU. Basically a discrete GPU is used recently by software developers as a security layer to prevent harm to the users system from any software plugins or software, that try to leverage any security vulnerabilities in a integrated GPU.
Another issue with the Core i3 is the high variety of CPU branding, as well as the competition with AMD. With the release of Intel Core i9, now there are 4 lines of modern Intel CPU's. It's a well known fact that manufacturers do not use all CPU's that Intel is currently manufacturing. Then there is the AMD CPU's that are crowding the space. Basically with this crowded space, there is little room for Core i3 to thrive.
Core i3 is currently a x86 or x64 architecture, thus unsuitable for use in low-end electronics like smartphones, that require ARM based CPU architecture. It would require Intel in investing to make ARM based Core i3 CPU's.