Well, it IS 10 years old, and that’s how long it takes them to bloom.
Has it been in the same pot for all of these 10 years? Maybe once it warms up enough by you, you could take it outside, wear gloves and re-pot? If you do, use the Cactus Soil that Miracle Grow makes. It’s good stuff!
The only other ideas I have is that it might have been over-watered, but you must have drainage, and are aware of that need if you have a drip saucer under the pot!
Can it be moved to the SUNNIEST spot in your house? That might perk it up some, too - and I, too, hope it blooms for you! How fun!
I once had a GORGEOUS Barrel Cactus. I was away on a training mission and the then-hub decided to take it out on the porch steps for more sun - but it rained for a solid WEEK and pretty much drowned. When I got home, I went to care for it and see if I could save it and it DEFLATED like a Souffle!
I didn’t divorce him for killing my Cactus - there were PLENTY of other reasons. ;)