[Question] Is the “business cycle” an actual economic principle?

E.g. In­vesto­pe­dia: Busi­ness Cy­cle has a sec­tion “Stages of the Busi­ness Cy­cle”:

All busi­ness cy­cles are char­ac­ter­ized by sev­eral differ­ent stages, as seen be­low.
1. Ex­pan­sion. This is the first stage. When ex­pan­sion oc­curs, there is an in­crease in em­ploy­ment, in­comes, pro­duc­tion, and sales. Peo­ple gen­er­ally pay their debts on time. The econ­omy has a steady flow in the money sup­ply and in­vest­ment is boom­ing.
2. Peak. The sec­ond stage is a peak when the econ­omy hits a snag, hav­ing reached the max­i­mum level of growth. Prices hit their high­est level, and eco­nomic in­di­ca­tors stop grow­ing. Many peo­ple start to re­struc­ture as the econ­omy’s growth starts to re­verse.
3. Re­ces­sion: Th­ese are pe­ri­ods of con­trac­tion. Dur­ing a re­ces­sion, un­em­ploy­ment rises, pro­duc­tion slows down, sales start to drop be­cause of a de­cline in de­mand, and in­comes be­come stag­nant or de­cline.
4. De­pres­sion: Eco­nomic growth con­tinues to drop while un­em­ploy­ment rises and pro­duc­tion plum­mets. Con­sumers and busi­nesses find it hard to se­cure credit, trade is re­duced, and bankrupt­cies start to in­crease. Con­sumer con­fi­dence and in­vest­ment lev­els also drop.
5. Trough: This pe­riod marks the end of the de­pres­sion, lead­ing an econ­omy into the next step: re­cov­ery.
6. Re­cov­ery: In this stage, the econ­omy starts to turn around. Low prices spur an in­crease in de­mand, em­ploy­ment and pro­duc­tion start to rise, and lenders start to open up their credit coffers. This stage marks the end of one busi­ness cy­cle.

If all you know is that mar­kets are anti-in­duc­tive, and there­fore an­ti­ci­pate a ran­dom walk with an av­er­age of 10%/​year growth, don’t you au­to­mat­i­cally ex­pect the stock mar­ket fluc­tu­a­tions to some­times look like bull mar­kets and re­ces­sions?

So does the “busi­ness cy­cle” add any ex­plana­tory power, or is it merely the type of retroac­tive non-ex­pla­na­tion that you get when you read a news ar­ti­cle about the 1-day move­ment of the stock mar­ket?

Maybe you can ar­gue that the busi­ness cy­cle is self-re­in­forc­ing due to psy­cholog­i­cal re­ac­tions.

But to the de­gree that the busi­ness cy­cle is a sep­a­rate un­der­stand­able phe­nomenon, can’t in­vestors use that un­der­stand­ing to place bets which make them money while damp­en­ing the effect?