Is housewares a double plural?

Solution 1:

Explaining why one thing changes and another doesn't is hard because these changes are often arbitrary. Take this as a partial answer.

Wares is used when there are multiple kinds of -ware being offered, such that a form with wares serves as a hypernym of many kinds of -ware. For instance, the first two definitions for "ware, n.3" in the Oxford English Dictionary distinguish the collective form in singular and plural. Earlier uses of both forms go back to Old English. See what happens in the last three entries for each:

Singular

c1820 Nursery Rime Simple Simon Met a Pyeman, Going to the Fair; Says Simple Simon To the Pyeman, Let me taste your ware.

1823 W. Scott Peveril IV. vii. 162 I am always provided with ware which a gentleman may risk his life on. (note: fulltext here shows that a cutler is speaking)

1844 A. W. Kinglake Eothen xviii. 299 The owners raised various objections to the display of their ware [sc. white slave-girls].

The ware in later use refers to a specific kind of good - pie, cutlery, or slave.

Plural

1776 A. Smith Inq. Wealth of Nations II. iv. ii. 52 A capricious man of fashion might sometimes prefer foreign wares, merely because they were foreign, to cheaper and better goods of the same kind that were made at home.

1834 G. P. R. James John Marston Hall I. xii. 159 I perceived..a man in the dress of a pedlar, with his box of wares laid down by his side.

1913 G. Edmundson Church Rome First Cent. v. 123 A fire broke out..amidst shops containing inflammable wares.

In later use, all of these wares are made up of several kinds of goods, or goods of indistinct type - Adam Smith is discussing goods generally, the peddler-dressed man may sell several kinds of goods, and the shops collectively may sell several kinds of goods that are inflammable.

This shift to a distinction between ware and wares feels recent, over the last few centuries. For example, almost a century before the 1834 example, a similar example involving a peddler appeared in singular, even though he would presumably sell several kinds of goods:

1748 T. Smollett Roderick Random I. viii. 55 He certainly intended to make free with the pedlar's ware.

Houseware(s) formed as a word at the time this shift in form was occurring. In the earliest example offered by the OED, under "house, n.1 and int.," houseware is singular:

1827 T. Carlyle tr. J. P. F. Richter in German Romance III. 87 I..wished that..I had given up the stupid houseware to all thieves and fires.

However, almost all later uses are in plural, save for one example of an appositive noun in singular:

1859 W. Barnes Views Labour & Gold 141 House-wares, that are now in shops of every town and village, were borne on strings of packhorses from fair to fair.

1921 Daily Colonist (Victoria, Brit. Columbia) 1 Apr. 7/1 (advt.)
Extra values in reliable house wares today and Saturday.

1971 Sunday Express (Johannesburg) 28 Mar. (Home Jrnl.) 9/3 (advt.) Housewares..Grapefruit knife..Bathroom Scales.

1990 Essentials Sept. 4/2 Pack your kids off to a new term with a..lunchkit from Thermos... The lunchkits cost £4.99 from department and houseware stores.

2005 N.Y. Times (National ed.) 20 Nov. v. 10/1 Shops like Colette, in Paris, where a selective collection of high-end housewares, clothing, CD's and art books are displayed side by side.

Housewares becomes a convenient shorthand for all the kinds of ware that appear in a home, following from the developing usage of wares compared to ware. At least one other word fits the pattern, and has been enshrined in bureaucratic use: smallwares (IRS):

Generally smallwares consists of the following categories: glassware, flatware, dinnerware, pots and pans, table top items, bar supplies, food preparation utensils and tools, storage supplies, service items and small appliances costing $500 or less.

As to the other question, it is hard to draw a strict line between hypernym and not, and therefore to explain why more words don't use wares. For example, kitchenware would serve as a hypernym of various utensils and appliances, including silverware and earthenware, but it maintains a singular form. So there is an element of arbitrariness afoot.