I’ve done that personally - an elderly gentleman and veteran in his late 70s in a situation of poverty known to me.
However, from a liturgical perspective, it would be an embarrassment to the recipient to do that in front of a congregation, and there are real mystagogical and emotional benefits for all participants.
And also I would note, the fact that the boys of the church now have clean and (and mostly healthy, but this isn’t guaranteed; flat footedness and various disorders of the bone structure are unfortunately not uncommon) feet is a very recent phenomenon made possible by the improvement in the standard of living in the US and the Middle East in the late 20th century. So the idea that this ritual is hollow because the feet in question do not require being washed is a new concept, based on a very recent turn of events, and in my view it would be quite wrong to abolish this liturgy on that basis. For example, suppose there should be a collapse of our technological civilization due to some catastrophe? As it is, for reasons I will explain, there are two countries with substantial, in one case, a majority Oriental Orthodox population, where the conditions I mentioned do not exist, and abolishing this liturgy now would result in it not being done under such conditions, aside from the loss of mystagogical definition.
In the case of Ethiopia, I don’t know if they do this particular liturgy, although I should like to find out, but if they do, that country, which is home the largest Oriental Orthodox church, the condition of health and cleanliness would unfortunately exist only in the wealthier parts of Addis Ababa and certain other cities and in the diaspora, since Ethiopia and Eritrea (which became independent in the early 1990s in a war that followed the collapse of the Derg regime) have both suffered poverty, famine and in the case of Eritrea, a brutal and oppressive dictatorship, ever since the Communist Derg regime came to power in the 1970s, strangling the Christian emperor Haile Selassie*, and before that endured nearly a decade of oppression by the Italian fascist regime of Mussolini.
But if you want to find examples of Eastern and Oriental Orthodox priests and bishops who have done a lot for those in need, including washing their feet, our synaxaria is full of them, into the 20th century, for example, St. John Maximovitch of Shanghai and San Francisco. Likewise the Roman Catholics and many Protestant denominations have done superb work; Mother Theresa, an Albanian Catholic, comes to mind (Albania also has a large Eastern Orthodox population; the evil and stupid communist dictator Enver Hoxha tried to suppress all religions but as soon as his regime collapsed, the Christian faith reasserted itself; alas so too did Islam make a comeback). But Mother Theresa is far from the only example. Indeed the charitable operations of the Roman Catholic Church are the boast of all Christendom in my view; their charitable operations are more numerous, larger and better organized than those of anyone else.
* Haile Selassie it should be noted was opposed to Rastafarianism and attempted to convert the Rastas to Orthodoxy, sending missionaries to them, with some success. Nonetheless to the chagrin of all Egyptian and Ethiopian Christians you will find some Rastas who claim to be Coptic, which they aren’t (they only claim this because the Ethiopians were part of the Coptic Orthodox Patriarchate of Alexandria until the mid 20th century); both the Coptic and Ethiopian churches take a very dim view of marijuana use, and what is more, the Ethiopian church even strictly limits alcohol consumption; Ethiopian Orthodox Christians get one ration of a mild church-brewed beer along with bread at a few vigils throughout the year, before standing all night in prayer, that being the limit.