Huge difference between the two. You can create a moat around your business, so that competitors find it hard to match the services and value you provide.
Vendor lock in is a moat created around the customer, so that they find it hard to switch even if someone else in the market is offering a better product.
I don't think there's a big difference for the customer. In either case the vendor has full grasp on those family jewels and can name any price for their product or service. See also: everyone eagerly awaiting an actual viable alternative to NVidia's GPUs. Are they a good product? Yes. Do customers want there to be a competitor so they can pursue a dual vendor strategy and do some price negotiation? Also yes.
But can you imagine needing a printer and having to buy another dumpster fire HP? Or buying an HP because you had HP-UX on your last computer? Ugh, what a dystopia.