God doesn't simply answer prayers for a show. He does it for people who are in need. Certainly someone who loses both arms and legs is someone in need and plenty of people that actually believe in god have been praying for them and yet it never happened. I guess god doesn't want to show us his existence that way, it would be too easy and it would make us atheists believe in him, he obviously doesn't want that
How really silly are you trying to be? Consider the following.
Make a real arm or leg. You can't do it. Science can't do it. After painstaking research, science is only finally finding out how to adapt the nature of a few animals that CAN regrow limbs, in such a way that they might possibly apply it to people someday. In other words, as far as science goes, regrowing limbs is still way beyond their reach.
What does this mean? This means that there is a lot of technology in growing arms and legs. Science doesn't have a clue, science is completely blind, regarding how to grow a limb from scratch without using some of the processes that nature has provided. To repeat, science has absolutely no idea as to how to take a bunch of chemicals and turn them into an arm or leg.
The point? The point is that regrowing an arm or leg requires a large amount of capability, way beyond anything that we can even imagine at this time.
So, where did you get your arms and legs that you have already? Didn't you get them free? Certainly you didn't buy them, right? You might have exercised them or trained them in certain ways, but if you hadn't gotten them free, there would be no way you could get them at all!
Again, the point is that there is a tremendous amount of "stuff" in the nature of arms an legs that is miraculous regarding anything that we can do to make them.
Now consider the miracles that Jesus did as recorded in the Bible. Some of them were done quite easily by Him. Look at the transfiguration of Jesus in Matthew 17. While Jesus and 3 of His disciples were on the mount of transfiguration, a man with a demon (epilepsy?) possessed son came to the disciples He had left behind at the foot of the mountain for help. But they couldn't heal the boy. The disciples couldn't cast the demon out as they had done at other times, possibly because it was epilepsy. Look at what happens when Jesus comes into the situation, Matthew 17:16-21:
17Jesus replied, “You unbelieving and perverted generation! How long must I be with you? How long must I put up with you? Bring him here to me!” 18Then Jesus rebuked the demon and it came out of him, and the boy was healed that very hour.
19Then the disciples came to Jesus privately and asked, “Why couldn’t we drive it out?”
20He told them, “Because of your lack of faith. I tell all of you with certainty, if you have faith like a grain of mustard seed, you can say to this mountain, ‘Move from here to there,’ and it will move, and nothing will be impossible for you. 21But this kind does not come out except by prayer and fasting.”
You won't ever get the things you desire along these lines of healing. Why not? No faith. The Bible section shown above shows why something as tremendous as regrowing arms and legs isn't being done in miraculous ways by more than a few people. They aren't praying and fasting enough in faith.
Again, why doesn't a small amount of prayer and fasting work to restore lost limbs? Because of the gigantic amount of "technology" within things like limbs. It is also why you lost any faith that you might have had years ago. You simply gave up when it didn't work out for you like you thought it should.