The problem is that as you get higher in OVR, training becomes exponentially more expensive. Training an 87 from level 1 to 2 costs less than 50,000 tp. Training a 97 from level 1 to 2 costs 750,000 tp.
As with you I realised that I had sufficiently good players but they were not trained up to max (nor close to it). But when I began focusing on training it became clear that it too was an expensive proposition, and has no "pay off" as you will never be able to sell that player again.
And with prices high in the auction house, it is difficult to get cards for training at a reasonable price. If prices begin to drop in the future as others have predicted, I will use that opportunity to max out my team. I also may pick up a few new ones as well.