I would have thought that the aluminum Briggs & Stratton would've been the cheapie, that the cast-iron Tecumseh would've been first choice.
Tecumseh made the cheapest engines.
They did also make good ones but their stock & trade was cheap throw away engines to supply the bottom end of the market because most people make heir final decision on price and 5¢ less will win a sale.
The bottom end has no loyalties apart from the $ so the first time some one offers a product 1 ¢ cheaper than your, you loose a customer & Tecumseh could not under cut the Chinese .
Going on a buying spree did not help their cashflow.
Why do you think Briggs suddenly decided to buy up bankrupt mower factories ?
To maintian a demand for their engines.
Whole sale I can buy a Honda copy for 1/4 the price of a Briggs and large scale users would get a lot better price than that.
Toro have gone to Lonscin engines on their domestic models and it time will use Chinese engines exclusively.
And a full cast iron engine is a lot cheaper to make than an alloy one.
On a governed air cooled engine cast iron is a substantially better material but the idiot public are sold on alloy because of its use in cars & motorcycles, where the weight reduction is a massive advantage to the end user.
This does not translate to mowers.