I think it helps that the Taxman port of Sonic 1 is probably the least overwhelming, as in it's still lavish, but has a less insane overhaul of goodies and upgrades to compete with over the other two. Taxman Sonic 2 had HIDDEN PALACE ZONE. How do you compete with that? I think if SEGA AGES Sonic 1 got patched with a bugfixed Spin Dash/Drop Dash and maybe a couple updates other releases have got since then like Sonic 2's Rumble feature, it could almost contend as a solid rerelease. It at least has a fair few features and engaging qualities that the Taxman port doesn't to balance it out.