Paste wax offers minimal protection. While water beads up on it, that is a manifestation of surface tension. It provides nearly zero resistance to water passing through.

Polyurethane does not stick well to things. I had to refinish a table like this a few years ago. The owner applied a coat of poly to make it shinier. (File this under: "It sounded like a good idea at the time.") Besides looking terrible, about 1/4 of the table top had poly peeling off.

Teak typically has a low-build finish on it. While generally thought to be "oiled" finish, it is usually a low build, very low sheen lacquer. Teak also contains natural oils that inhibit a lot of finishes from curing or curing hard. It needs a little knowledge and extra care in finishing.

As I see it, you have a couple of choices if you can't or won't cover it:
- Discipline to treat it with more gentleness, use placemats, etc. No finish is immune from physical damage. It's all a matter of degree and type of damage. The strength of the wood and its substrates also becomes a limiting factor. I have seen where people scratch and chip even the "indestructible" finishes.

- Take it out and have someone strip and refinish it with a different top coat. What top coat that might be will depend upon the "system" that the place that you go uses, or if you are doing it yourself, what you are able to do based on your skill level, equipment and working environment.

Despite this advice, if you choose to apply poly over the top and it does not work, you still have the strip-and-refinish option, it's just that you might be forced into it. The biggest mistake you can make with poly is to apply it too thick and un-thinned. Thin it down up to 50:50 mineral spirits, so you can wipe on the finish with a rag. Very light coats. While you will need more coats to get the same dry thickness, each coat will go on faster and is more foolproof for a beginner than brushing a good finish.

wow bobsmyuncle! so helpful! I am going to phone around and see what furniture refinishing places around me would charge. I will likely not attempt anything on my own at this point.