I think if all you want to do is ride then a weanling isn’t for you. I’ve had my girl from a foal and have really enjoyed all the different steps even the not so good days where she was trying new things out on me. It was fun watching her grow up, teaching her new things and there was even the day I realised she had it all worked out and was a “big girl”. Yes it costs money to give them the right start.
One reason I wanted a baby was because I have owned a number of horses that I bought at 4 and upwards who haven’t worked out due to various issues mostly soundness. With this in mind I now know her entire history from what she was fed, breeding back ground, training, maintenance, personality and injuries. To me knowing all of this gives me a huge advantage on what I will and won’t do with her. I believe I own a horse I probably couldn’t afford to buy now which is the benefit of getting them young IMHO.