Some people can switch their IP easily. I used VPNs extensively on 4chan, not to shit up the board or anything, just because I was catching annoying 3day bans for the most mundane shit, like getting a ticket for jaywalking. When you use VPNs on 4chan, everytime you switch your IP you HAVE TO DELETE YOUR COOKIES, that means waiting 15 minutes EVERY time you need to post.It made no difference. You couldn't tell if a thread was 1 person or 100 because phone posters can hop IPs easily. Bots can use different IPs or Indians with a wall of smart phones can jump in and out of a thread.
You are talking without having the actual experience of evading and hopping on 4chan, you are assuming things. I know this because i learned from real shitposters. The 15 minute wait was a HUGE annoyance to VPN users or IP hopping. Removing the IP count was just shady and scummy bullshit given that the 15 minute wait was in place everytime you had to delete cookies to switch your IP
You can samefag your thread with a VPN and make it seem like it was all done by unique IPs, but that takes time and effort (wait 15 minutes, post, switch IPs, delete cookies, switch ip, wait 15 minutes, post). you can spambot and advertise on 4chan, but you can do it ONLY with a 4chan pass and jannies will turn a blind eye, because it's a tacit agreement. "you jeet up the thread, but you gotta pay"