I did create and verify relatively large (30-50) number of accounts few times. It's a time consuming procedure, so lately I prefer to buy verified accounts in bulk.
You might check digital goods section specifically invites and accounts section here i saw some people providing this service, It's really simple to make lot of gmail account but people are just too lazy to do this task that's why they bought the account in bulks.
When did this happen? Few weeks ago I registered 20 accounts and wasn't asked for phone # verification.
I think the verification will be needed when the account creation happened simultaneously with small time interval.Because to stop the bot creations but it will not be problem if we create the more Gmail from same IP with much time gap or using VPNs.
Yes you are right, google will detect those who trying to create multiple accounts, the alternative way is buying gmail account from other people or purchase number card and create the account by yourself.