Tubs are superb: they ride so well; but there is a vast difference between cheap ones and good ones.
I’m running Vittoria Pave, and have been for a few years (not huge mileages). One of them punctured. Using the internet, I made an incision, found the hole in the tube, patched it and sewed it up. It’s a latex tube. It loses air a bit quicker than its partner, but is good for a couple of rides. I know, “Bullshit” you cry, and I don’t blame you. But it is possible and one day I will do a forensic YouTube “tubopsy” to prove it!
Anyway, the bigger problem is prolly the lack of availability of more tubs rather than repair skills.