What i meant by it being a once in a lifetime opportunity is that, the job that i do often is really unpredictable in terms of what free time i have. Learning by doing the odd lesson here or there, coupled with the unpredictability of the weather and not being able to commit to lessons until very short notice, could mean i'd take years to get my license. While you'd come out of this apporach with a "high hours" PPL. I don't necessarily think it's going to make you a better Pilot, since you'd spend most of your time relearning things which had been forgotten!
I don't necessarily have a problem with taking time to get the PPL, i also don't think that getting your license is a "check box" event but there is absolutely an incentive sometimes towards regular and consistent training, and unfortunately that's a difficult thing for me to commit to without some sort of "intensive" training.