"How would a 40+ year old corporate pilot (light/midsize jet) who hasn't flown 121 for 10+ years look when compared with a 25 year old RJ Captain, or military pilot?"
IMO you'd do just fine *IF* you have turbine PIC time. 500/1000?
As far as the answer to "why did you not accept the recall at US?" -
1. junior
2. economic uncertainity (market collapsed)
3. US just out of BK
4. uncertanity/unrest of AW/US seniority list
Getting hired today will hopefully be a different story. At AA it will probably be a 10 yr upgrade (+/-)(junior bases) and w/b CA 3-5 yrs later. That would leave you with 15 yrs as Captain and maybe 10 yrs as w/b Captain if you get hired at the start of the hiring cycle.
Retirement data is out there. Do some analysis on where the curve is in your favor.
Good luck.