1)Netbooks didn't really get eaten by tablets. The Netbooks were just very under-powered machines aimed at a very niche market of people who just wanted to surf the web and check email. They had extremely small storage options, cpu option, OS options, RAM, and i/o options. I bought a used Dell and it was a toy just to bring on vacation 10 years ago. That was it. Vacation. I never used it again because it was basically useless for any kind of day in/day out device.
2)Tablets are essentially the Amazon Fire and iPad. They really haven't damaged the low end laptop market from what I see. I still see plenty of people with $500 laptops which I consider low-end. Sure, there may be some 1.5 year old in-stock only super sale at Walmart where a $500 laptop is on sale for $329 because they want to get rid of them. There are some Dell and other vendors selling brand new machines for $299 but I don't know who's buying them. Anyone who wants a laptop for true laptop needs (more than just surfing and email) is spending $700 and up.
DigitalGuy has some great comments above which I agree with. But on your topic as a whole, the iPad/Tablet will never replace a true "personal computer" as it has been defined the past 35+ years (physical keyboard, phyiscal mouse, monitor, upgradeable/replaceable components). Designers use personal computers and workstations to CREATE iPads/tablets and other electronics devices. Look around your house and every single thing that runs on electricity has been designed on a personal computer over the past 35 years: cable box, alarm clock, stove, microwave, phone, shaver, hair dryer, answering machine, monitors, tvs, stereo receivers, speakers, etc. Not a single one of those can be created on an iPad Pro. Even most non-electric things are created/designed on personal computers: Lego blocks, scissors, picture frames, soda cans and bottles, sneakers, jackets, tires, etc. The iPad is simply not made for the kind of granular control that a mouse or keyboard can give. Not to mention working on a 12" screen. The last time a personal computer was connected to a 12" screen was probably 1983 (such as all the Apple //e monitors or even the 13" Commodore 64 monitors). Ultimately, the human finger cannot match a mouse or keyboard. The iPad is a touch-centric device. Period. Also, the iPad may begin to have the CPU/GPU for CAD processing, but it doesn't have any integration to a real file system or doing the actual design work that is industry standard or day-in-the-life of a CAD person.
The humans that design things cannot use an iPad (Pro) for design work.