Otherwise, soil would get progressively more alkaline every third year to the point that it would be infertile.
Think that's a typo and you mean soil gets progressively more acid.
Anyway Jim, my soil is genuinely alkaline, and the chemical ph tester went to a darker green than the example strip will samples from all over the garden! Do test in different places as you may have had a spurious result. Also, did you follow the instructions in using the tester? I had one of those once and I thought you were supposed to dig up some soil from 6" or so down and mix with water etc. etc. but I'm typing from memory as its not in front of me.
Other things to look for on alkaline soils are that lilacs grow well and hydrangers go pink rather than blue unless treated (untreated ones here go pale pink to white!).
I do give my soil as much garden compost as I can make and the Christmas tree shreddings but other than that I don't bother trying to acidify my soil, I seem to be able to grow all sorts of crops without too much bother. I grant you I don't grow much in the way of brassicas due to space limitations. Apparently my raspberries won't last that long and I wouldn't try to grow blueberries straight in the grown (if I grew them - I don't like them so I don't).
Its not a case of good or bad in alkaline vs. acid. Its what you've got. Its worth knowing so you do or don't try planting something that has to have acid soil straight in the ground (rhodadendrons, azaleas, camelias or blueberries).
Sandy soil generally isn't alkaline I think so I do wonder if you had a spurious result.