reCaptcha has multiple options to weed out bots that do not involve ads. Including one that just involves clicking a checkbox to say you are not a bot. When an ad interferes with site functionality, the ad should be removed.
Recaptcha has also already been bot cracked in the past and as such can be bypassed. Solve Media hasn't to date, we're looking at other features with a similar track record, as the other side to this is it won't show to people using adblock.