the issue you have though it's in a lot of airlines T&C's that you have to have 6 months valid on passport to fly with them regardless of the travelling countries entry requirements. I would also make sure you fully read the airlines T&C's before making the decision not to renew passport. Ours was a Emirates codeshare flight with Bangkok Airways that we had our issues with. Regardless of immigration entry requirements, it's the decision of the airline as to whether or not they allow you to fly with them.
We had 6 months on our passports on the way out to Thailand but didn't have 6 months on return by one day last month and our airline wouldn't let us check in online as our passports weren't valid for 6 months even though we were leaving Thailand and going back to UK, we had a right faff on at the airport trying to check in. You might get in with no issues but take it first hand you might have issues leaving as we did just last month. Its up to the airlines whether they'll let you travel or not will less than 6 months on your passport. We flew home from thailand on 16th Nov and our passports ran out on 15th May. We were told that if our airline refused to let ur travel as we didn't have 6 months left we would have to go to the British embassy for an emergency passport and we would have had to pay for 2 new flights home, we were staying in phuket. If you can get a replacement passport, I would recommend it to have peace of mind and not face the issues we did.