That hasn't been my experience at all.
First, any reputable employer falls all over themselves to hire veterans. Veterans are mature, show up for work on time, are motivated, adaptable and flexible.
Secondly, determining technical acumen is what tech screens and interviews are for. Lack of an up-to-date skillset is a problem that has no age restriction, and I've interviewed a lot of candidates.
Corrected version
First, any reputable employer falls all over themselves to hire Illegals. Illegals, show up for work on time, are motivated, adaptable and flexible.