Guys, Why would a guy message for a date then never reply?

A guy I haven’t talked to in awhile (we’ve never met but have briefly talked/flirted before online) randomly messaged me on instagram the other day saying “dinner soon?”. My friends said I had to agree, and I AM interested in him, so I replied “I’m free Friday”. He hasn’t replied since. It’s now Wednesday night and he messaged me originally on Sunday. He’s been posting on instagram and has even liked my instagram stories in the meantime, but has not replied to me. Whatttttt? I’m too old for games lol. Horrible overthinker, would love some insight!!

Updates
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Update: today is Friday (the day i stated i’d be available). No word from him since his initial DM the prior Sunday. Well, he texted me this morning “good morning”, asked how I slept and then when I cut the small talk and asked what he was doing tonight/this weekend - no reply. Silence. WHAT is this guy doing?
Guys, Why would a guy message for a date then never reply?
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