I disagree, for his described usage. For example, today an i5-8600, i5-8500, or even i5-8400 would suit the needs of the OP just fine for quite some time.
For Ryzen, it would depend upon the GPU he has. I wouldn't upgrade to Ryzen without a GPU that can support Netflix 4K, for example. That's not necessary on the Intel side, because all their CPUs support Netflix 4K with the on-board GPU.
I didn't mention the Coffee Lake i5 CPUs, but I did mention the Ryzen 2600(x). But I agree a mid-range Intel CPU might last him for his stated number of years he wants it to last. It really all comes down to what his current usage (and planned future usage) is. Everyone's needs are different, and I was just going on the fact the OP stated he has 60+ browser tabs open, plays games, and downloads "stuffs".
I was just pointing out that when it came to my son's PC usage, I was very short-sighted with two CPU purchases. After he surpassed the i3 relatively quickly, I should have gone to an Haswell i7 instead of cheaping out, and buying the i5 (No Ryzen at the time). One of the things he does (and which I always tell him not to do) is leaving 50+ browser tabs running with HD Youtube videos, and such. He also tends to just leave the various programs open he uses to edit/record/stream videos until he is done for the day. Along with various Microsoft Office documents also open at once, that sort of thing will choke the "budget" CPUs pretty badly.
I personally don't understand leaving so much open at once (maybe it was because I grew up in an age where RAM and HDD amounts were significantly lower than what is the "norm"now), but I rarely have more than 5 browser tabs open at any given time, and once I finish using a program, I close it out. Having a fast NVMe drive with plenty of RAM, it only takes a few seconds to reopen stuff if I need to.