So what's your argument? Do you always have labor camps and just never delete to collect?
And I think you'll see that the benefits from infra purchases are slowing down quickly at the 3999 level. You aren't getting the gains of happiness improvements anymore. I've been sitting at 3999 for two months just collecting tech and buying wonders. By my brief calculations, spending $70M on two wonders yielded nearly the same gain as jumping to 4999 which would cost $72M with my current tradeset.
There are a million ways to play this game, but IMO, you're making a mistake to collect taxes while holding labor camps.