Feel free to correct me if my memory is wrong because it very well could be.
The solution I considered was paying people in Africa to sign up for gmail for me, and I'd pay them per account. I figured I'd only need 50-100 per month, so the low volume might make it possible. They often have smartphones, and amounts that are too low for you to bother with might be a decent payday for them for 5 minutes work.
Now, I know what you're going to say... Youtube detects copyrighted works, won't let you upload them. That part was easy.
Just invert the video color, and flip it upside down. Then the lua script for VLC would de-invert and unflip it. And I could even bring in the audio from another site (VLC allows muxing), since Youtube uses audio signatures more than they do video signatures for that stuff.
I had a prototype going for awhile. Called it "Space Potato Channel". It just played videos others had uploaded (wrote a little backend to schedule movies). If you tuned in 5 minutes late, it'd show the video 5 minutes in, etc. Then I learned about how the NSA was giving tips to law enforcement and doing the parallel reconstruction thing, and I reconsidered my scheme to become a bitcoin millionaire.
Long story short, gmail accounts were never something I thought would be much of a problem.
Hang out on any blackhat SEO forum (or more illegal carding shops, etc. I would imagine) and you'll see plenty of guys peddling this service.
Incidentally, the youtube method you're describing has been automated many times. My first real PHP project was a script that found popular videos on non-youtube sites, downloaded them, watermarked them with my blog URL, and uploaded them to youtube. That resulted in a fair amount of direct traffic.
If you trawl around youtube these days you'll see plenty of watermarked videos that are clearly not original content. But as long as nobody is claiming copyright -- which nobody is doing for cat videos -- Google doesn't give a shit. Honestly, uploading non-original videos to Youtube only helps their numbers.
I think a common misconception is that companies care about fake/"spam" user accounts on their services. But what incentive do they actually have to ban them? In the world of venture capital, user numbers are an incredibly important metric, so as long as they aren't actively diluting the service for other users, companies have an incentive to allow them to propagate and pad their stats.
Take Snapchat for example. Looking at my friend request page, I have dozens of obviously spam accounts asking to be my friends. Is Snapchat including these accounts in their user numbers? Almost definitely. In fact, they probably even count as "active users" because they are "sharing photos" so often!
One has to wonder how many popular services have been built on VC money given to them on the presumption of accurate user statistics, when in reality 20-30% of accounts could be shills. Snapchat, Twitter, Facebook... There are tons of fake users on all of them, and yet these companies make relatively little effort to exclude them from stats (except, of course, when reporting monetization per user).
Using some privacy settings and VPNs will get you more Captchas on Google services also.