I'm sure a professional would do more than this.
Am I right?


Nope, in fact most don't even bother with the topsoil. Bad mistake.


The "professionals" are out to make a quick buck and are only interested in making certain that the grass germinates and looks good
for a few weeks, after that, anything that doesn't look great can be blamed on you.

Much simply depends on how much work you are willing to do and how much you will spend. If you really want to do it right, find a
good source of compost/organic material and rototill about as much as you can afford into the topsoil. This, however, requires a
tractor for anything beyond a small lawn. In our area, I can get good mushroom compost delivered for less than topsoil. The correct
pH, and fertilizers won't do a great deal of good if you have little organic material in the soil in order to hold the fertilizer
and water. In Texas, compost will hold moisture so one doesn't have to water as often. The "professionals" only care what is on the
top 1/2" of soil, because that is all the further the roots are going to travel for a few weeks - If you are interested in a really
good lawn, what is down 4 or 6 (or even more) inches is really more important. ...and you aren't going to get there without some
heavy duty work that the "pros" won't be able or willing to do. ...and the advice about watering deeply is irrelevant if you don't
have good enough soil to allow the roots to grow deeply in the first place. I chuckle every time one of the neighbors tells me
about the sod layers who have told them about watering infrequently and deeply after I observed those same sod layers place their
sod over hard packed clay, sand, or rock, knowing that the roots of that sod don't have much chance of penetrating beyond the inch
or less of semi-suitable topsoil in the sod itself. One of the neighbors even consulted with a friend who manages golf-course grass.
I couldn't believe that the guy provided all good information about pH, grass type etc., but failed to mention to the neighbor that
the soil in our area is very fine silt that packs as hard as a rock that holds water very poorly and has no organic matter in which
to hold water or allow the roots air in which to breath and spead their roots. Presumably, the manager assumed that the neighbor
wouldn't want to do the work and spend the money on compost (we have a mushroom facility down the road, which will used compost at a
good price), as I am certain that he understands this point.

....and by the way, what the "pros" call topsoil in this area, I call sandy fill material.

Work on golfcourse greens starts over a foot below the surface. If you really want a nice lawn, you have to start thinking about a
few inches below the obvious surface conditions.