Alexander was a super-crawler. He crawled for more than 6 months and he didn't show any interest in walking until around 17 months. Then, he suddenly decided to try walking, and went 4 steps. He didn't try again for another month. He was about 18 months when he started walking. We got him "walking wings" and that seems to help him get the motivation.
If it were me, I'd bring it up at my next visit and get her evaluated if I was still concerned. I would think getting the tubes might set her back a little (discomfort from surgery, etc.), if anything. But, I assume she's sick often or getting tubes wouldn't be necessary, so maybe once she's feeling well on a consistent basis, she'll be more inspired...
Maybe you can ask daycare to encourage her more? Maybe they are actually reinforcing the "crawling is better" perspective. If she's small, maybe they've kept her in a "younger" room so she doesn't see as many young walkers?
Just some thoughts!
Wishing you luck. And, I don't think you have any reason to be especially worried. Normal range for walking is something like 11-18 months.