lol just because there is a newer version doesn't mean the older version is suddenly non-existent.
If the OP is asking about a specific card, I don't think it's a good idea to assume a different card.
Anyway, the GTX750ti is not a replacement card for the GTX750 just as the GTX650ti was not a replacement for the GTX650.
Have they stopped making the GTX750? Yeah probably. The GTX950 was the official replacement.