We reached that point years ago, and if you have to buy an eBay VCR when yours fails, your conversions will be lower quality than if played on the machine they were recorded on. VHS sucked that way.
The good news is that Time Base Correctors are inexpensive now, so I was able to fix flagging and color problems caused by playing on a different machine in most cases.
I had a huge tape collection, 75% of which turned out to be worthless because much better copies of the shows and movies are now available, but I did convert the remaining 25% to MP4 files. A few tapes were completely unplayable because time is very hard on magnetic tape.
I can't believe anyone would fail to upgrade home movies to a durable format, and just wait for them to degrade into uselessness while planning to convert them someday. That's destroying things via procrastination that should be handed down to your descendants.