Germany actually has over 200 ICE train sets, not 35. That's also an underestimate of service availability as a lot of the international services are provided by neighbouring countries high-speed trains. DB sends lots of ICEs on services to Switzerland and Denmark but not so much France and Belgium. It's not unusual to take a seat on a Thalys or SNCF TGV for a domestic trip within Germany.
The problems in keeping them running are pretty much limited to air conditioning breakdowns (someone didn't realise that the temperature here exceeds 30°C most summers).
They also run at pretty much full capacity most of the time and are the only part of the rail service that receives no direct public subsidy. It's a popular and generally functional service.
You are welcome to some ICE-1 at knock-down price in a few years when they get decomissioned, no need to buy your own brand spankers. Alternatively please take Eurostar's increasingly-decrepit rolling stock off their hands so they can build something with comfortable seats.