Look up "Long" range spells: 400 ft +40 per caster level. So
Fireball has a minimum range of 400 + (5 x 40) = 600 feet. That 120 squares.
Next look up "Medium" range spells. 100 ft + 10 per caster level. So
Lightning Bolt has a minimum range of 100 + ( 5 x 10 ) = 150 ft. That's 30 squares.
Magic Missile is in that same category.
It's only the "Short" range spells and powers that have a problem reaching 30 inches.
And , by the way, Warlock's Eldritch Blast has a range of 60 (12 inches), not 50.
Most weapon ranges in D&D make a compromise between realism and what fits on a battle mat. On most tabletops, you can't plot the
Fireball minimum range. (10 foot battle mats are even less common that 10 foot game tables.)
I once wrote a superhero game that had range increments for powers based on the user's Dex: For some powers it was Range in Feet divided by user's Dexterity score, with fractions rounding down. Others used Range in Yards, for the longer range abilities. Personally, I think something like that would be an improvement if applied to D&D.
In context of the current discussion, putting Longbows on a "Range in Squares" standard, the average Joe would suffer -1 for over 50 feet and -2 for over 100. That's pretty close to what they have now. Higher Dexes would have longer range increments in general.
Crossbows could be set at twice that, since they're easier to aim. So at 110 feet, when the Longbow is at -2 for range, the Crossbow would only be at -1.
I'd also base maximum Bow range (any type) on the bow's Mighty ranking. Heavier bows shoot farther in the real world, why not in the game? Again, because of the heavier draw on a crossbow, they would generally rate higher.
There's a thought: Want to make crossbows less lame? Allow them Mighty rankings (master worked bows only). If the Rank is higher than the user's Strength then they need a Strength check to cock it. DC is 15 +2 per Mighty rating.
That would bring the damage potential back in line with Composite bows.