I think it is unrealistic to expect Austria after World War I to become as decentralized a federation as Switzerland. Post-1848 Switzerland after all was the result of a coming together of cantons that had previously been virtually independent--united only by a loose alliance before the Sonderbund war. These cantons moreover were divided from each other both by language and by religion. A fairly loose federation was therefore the logical solution to avoid more such civil wars while preserving unity. Austria OTOH was not a coming together of more -or-less-independent states like Switzerland, the US, or for that matter the Kaiserreich; nor were there serious linguistic, ethnic, and religious differences among the
Länder (except to the extent that Vienna was perceived to be "godless" in some of the countryside). Indeed, federalism was not on German-Austria's original agenda at all. The 1918 Provisional National Assembly contemplated a unitary state that would soon join Germany. The Allies soon made that impractical, so the 1919 Constituent Assembly faced the question of a unitary vs. federal state with the Social Democrats (the largest party) favoring centralism and the Christian Social Party favoring federalism.
https://en.wikipedia.org/wiki/1919_Austrian_Constituent_Assembly_election The federal constitution actually adopted was a compromise.
It is true that "In 1919, Tyrol, in a hopeless effort to reunite with its southern part which had been annexed by Italy, declared itself a free state. In Vorarlberg, a referendum on acceding to Switzerland, held in 1921, was affirmed by ninety-nine percent of the voters. In the same year, referenda in Tyrol and Salzburg on joining Germany were supported by strong majorities of voters.
None of these initiatives had a reasonable chance of success. [my emphasis--DT] "
https://books.google.com/books?id=5w94DwAAQBAJ&pg=PA14 I think that last sentence is the key; since the Allies would not allow the Austrian state to break up and have parts of it join other countries, there was no need to appease these areas with extreme decentralization.