Fresh links often give you a little boost than then fades with time, especially with lower quality links.
Also if you were spamming the links (eg.profiles and blog comments), some of those backlinks will be being deleted by moderators. Especially in the case of profile links, often as more profiles are made on each particular site, your own profiles get pushed way down the list, become less visible on the site and will eventually be dropped from the Google index, especially if your profiles have no backlinks of their own.
Also bear in mind that while you might stop creating links for a while, all of your other competitors are going full steam ahead with whatever tools they have at their disposal. Your number of links is thus a constantly diminishing proportion of all the links that are out there in your particular niche... You gotta keep on the hustle.