Like a lot of things, you try and try to fix or rebuild, but sometimes the only real answer is to just get new. I would have done the same things you've done and probably strung it out just as long.
I fought wells and pumps for years, but when the county ran the water line past the property and asked me where I wanted my meter, I told them that I was so glad to see the water line, they could put the meter any darned place they wanted. Over the past 26 years I've spent a lot of money on water bills, but my water has never run out, I haven't had any pumps go bad and I haven't been up all night fighting a pump problem so everyone would be able to take a shower the next morning.
Good luck on your new well
I fought wells and pumps for years, but when the county ran the water line past the property and asked me where I wanted my meter, I told them that I was so glad to see the water line, they could put the meter any darned place they wanted. Over the past 26 years I've spent a lot of money on water bills, but my water has never run out, I haven't had any pumps go bad and I haven't been up all night fighting a pump problem so everyone would be able to take a shower the next morning.
Good luck on your new well