Yes, RR, what you are referring to IS a fact, and can be and IS caused by one or both, even a third element - alignment, dirty/clogged heads AND worn heads. The tape travel path, how the heads are aligned and their wear and/or accumulation of debris all contribute to either the results you note, or to the possibility that your recorded tape will ONLY play on that deck or camcorder.
Why, because due to the slight misalignment, tapehead path wear, clogging, etc. the tape is not recorded according to original specs and settings. Slightly different recording levels, qualities or paths on the tape's magnetic particles...a host of variances, can make that tape ONLY playable from the unit from which it was recorded. Attempting to play it on other units will or can result not only in faulty tape playback, signal and impossible digitizing or re-recording, but can actually further damage the tape to the point that nothing can resurrect its content.
However, just like the joke where a guy takes something in to be repaired and the repair person hits, thumps or bangs it, gets it working, then charges $500 for the service. The customer, having witnessed the apparently simply process, complains that all that was done was a thump or bang. "Yeah," the repair person replies, "but you paid me for knowing where to do it."
You DO NOT want to go into such a complex unit as a camcorder with its tape rollers, drums, pinch-rollers, carrier system misalignment and attempt to "have at it" with a set of jewelers tools from WalMart, canned air, or even a wet/dry head cleaner. There are too many things that a person who has no training or experience, and some of the equipment necessary for proper alignment and adjustments, tension spring replacements, etc. can make worse, causing irreparable damage.
Some of these people might overcharge, take advantage or even NOT know what they're doing, but the right places, with the right people, with the right tools, training and reputations, who represent the major camera manufacturers, will do it cheaper in the long run, lasting for a longer period of time, and without (hopefully) making the problem, or something else, worse in the process. "Normal" people shouldn't try fixing cameras and related equipment, nor should they attempt to diffuse bombs.