The problem with analog, is that (using inexpensive equipment) the copies must be done realtime. In other words, if you have 6 hours on a tape, it will take 6 hours to copy it. The good news is that once you copy to a digital format, the copies will no longer degrade.
There are also
services that will do this for you, if you value your time. They can convert video tapes to standard DVDs, usually at a fixed rate per hour/tape. Check your local yellow pages